Skip to main content
PLOS ONE logoLink to PLOS ONE
. 2023 Jul 26;18(7):e0288995. doi: 10.1371/journal.pone.0288995

Portable digital devices for paediatric height and length measurement: A scoping review and target product profile matching analysis

Tasmyn Soller 1,*, Shan Huang 1, Sayaka Horiuchi 1, Alyce N Wilson 1, Joshua P Vogel 1,2
Editor: Nandita Perumal3
PMCID: PMC10370750  PMID: 37494355

Abstract

Background

Routine anthropometry of children, including length/height measurement, is an essential component of paediatric clinical assessments. UNICEF has called for the accelerated development of novel, digital height/length measurement devices to improve child nutrition and growth surveillance programs. This scoping review aimed to identify all digital, portable height/length measurement devices in the literature or otherwise available internationally. We also assessed identified devices against the UNICEF Target Product Profile (TPP) to identify those of highest potential for clinical and public health use.

Method

We searched four databases (Medline, Embase, CINAHL and Global Health) and the grey literature between 1st January 1992 and 2nd February 2023. We looked for studies or reports on portable, digital devices for height or length measurement in children up to 18 years old. Citations were screened independently by two reviewers, with data extraction and quality assessment performed in duplicate and disagreements resolved. Devices were evaluated and scored against the 34 criteria of the UNICEF TPP.

Results

Twenty studies describing twelve height/length measurement devices were identified, most of which used prospective validation designs. Additional devices were found in the grey literature, but these did not report key performance data so were not included. Across the twelve devices, only 10 of 34 UNICEF criteria on average could be fully assessed. Six met UNICEF’s ideal accuracy standard and one device met the minimum accuracy standard. The Leica DistoD2 device scored highest (41%), followed by Autoanthro in a controlled environment (33%) and GLM30 (32%). These devices may be high potential for further assessment and development, though further research is required.

Conclusion

While 12 portable, digital devices exist for child height/length measurement, insufficient data are available to fully assess whether they meet the industry’s needs. Although some devices show promise, further research is needed to test the validity of these devices in varying contexts, and continued development and commercialization will be important to improve reliability and precision of these devices for widespread use.

Introduction

Routine anthropometry of infants and children, including weight, length/height and head circumference are essential components of nutritional assessments [1]. Measurement of height (standing up) for children aged 2 years and older and length (lying down) for children aged less than 2 years allows for detection and monitoring of stunting, wasting and obesity in children globally [2, 3]. Stunting and wasting are both forms of under-nutrition, and are significant impediments to human social and economic development. Stunting, defined as more than two standard deviations below the median height-for-age/length-for-age, affects approximately 162 million children under 5 years worldwide [4]. Stunting has long-term physical, cognitive, educational and economic consequences for individual children, as well as their families and communities [5]. Wasting is defined as more than two standard deviations below the median weight-for-height/weight-for-length and indicates recent and severe weight loss [4]. If undiagnosed or untreated, wasting is associated with a higher risk of death [4]. Conversely obesity—a body mass index greater than 3 standard deviations above the WHO growth standard median—also has significant health implications for children. Globally, 39 million children under 5 and 340 million children over 5 are overweight or obese [6]. Obesity is itself a non-communicable disease, and a risk factor for the development of other chronic conditions which lead to premature death and disability [6].

Given the physical, cognitive and developmental implications of poor nutrition, accurate anthropometric assessment of children is an essential public health practice, and ensures stunting, wasting and obesity are detected and treated early [1]. In addition, routine anthropometric measurements form the basis of critical health indicators for monitoring children’s health at a population level, which can assist in evaluating whether health and nutritional interventions are working, and also to assess global progress towards the Sustainable Development Goals [2, 3].

Measurement boards (stadiometers) are currently the gold-standard tool for obtaining child height and length, including in community-based child health surveillance activities [7]. While they have been in widespread use for decades, they are cumbersome and heavy [8]. The process of manual data collection also increases the risk of transcription errors, negatively affecting data accuracy. A digital, accurate and precise measurement device would thus provide significant advantages for clinical assessment and nutritional surveillance of children. If such a device were portable, lightweight, and reliable, with simple data storage and transfer abilities, it would make child health assessments easier. This is especially pertinent in resource-limited settings, where the large, cumbersome measurement board can be particularly difficult to transport and use, and reliable data transcription and record-keeping can be challenging.

UNICEF has highlighted the need for innovation in developing height/length measurement devices that can improve nutritional surveillance and clinical assessment of children. In 2017, UNICEF published a new Target Product Profile (TPP) for digital devices for measuring child height/length, which describes the required operational, performance, usability and commercialization requirements [9]. This TPP was intended to inform and guide new product development by commercial entities, yet it also provides an objective set of criteria by which a novel device could be evaluated. That is, assessment of device capability against TPP criteria can help identify those devices that best meet pre-specified clinical and operational needs, or the most promising candidates for further development. A TPP-based matching approach has been used previously to identify high-potential candidates for new obstetric medicines [10].

While a number of digital devices have been tested or are commercially available, no previous review has assessed the number, characteristics and quality of these devices. Furthermore, no review has evaluated whether tested devices meet clinical and public health requirements, which is essential to consider in order to bridge the gap between device development research and real-world needs. We aimed to identify and evaluate all portable digital devices for child height/length measurement. We also aimed to assess all devices against the criteria within the UNICEF TPP, in order to identify high-potential devices for further development or implementation.

Methods

Study design

This was a scoping review conducted in accordance with the Joanna Briggs Institute Methodology for Scoping Reviews and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) standards, using the Arksey and O’Malley methodological framework [11, 12]. The research question and study selection criteria and analytic framework were developed using multidisciplinary expertise and consultation within the scoping team to guide the search criteria and applicability of data for extraction. An analytic framework was developed using the 34 criteria of the UNICEF TPP (Fig 1), against which all identified devices that met the eligibility criteria were assessed [9]. The review protocol was registered online through the Open Science Foundation (OSF) [13]. As a scoping review of publicly available data, ethics approval was not required. No patients or members of the public were involved in the design or conduct of this review.

Fig 1. UNICEF target product profile criteria.

Fig 1

Eligibility criteria

Eligible studies were primary research studies that used any study design and conducted in any country or setting, provided that the study involved the use of a digital height/length measurement device in children under 18 years. Relevant product-related information, device manuals and webpages for any identified devices were also recovered during the grey literature search. Devices found in the grey literature only were included in the analysis if there was evidence of assessment of the device’s reliability and precision, which are essential criteria as per UNICEF’s TPP. We searched the literature from 1 January 1992 onwards, which captured 30 years of data, allowing for a thorough evaluation of contemporary products. Studies on conventional measurement tools only (i.e., height board/stadiometers) were not included. Systematic, scoping or narrative reviews were not eligible, but if they pertained to the review topic of interest, the references were checked for any potentially eligible studies.

Literature searching and eligibility assessment

We searched four databases—Medline, Embase, CINAHL, and Global Health–on 18th January 2022 and updated the search on 2nd February 2023 (Appendix 1 in S1 Appendix). We decided on these databases following exploratory searches and consultation with an information specialist. This specialist also developed search strategies for each database, combining relevant synonyms and search terms for height/length measurement, children and devices. We also used Google searches to identify any height/length measurement devices that were commercially available at the time of searching. These were run in incognito mode, with location and trending searches turned off. These searches used various combinations of structured search terms and synonyms similar to the formal literature search, and we inspected the first 50 hits. Targeted searches were also conducted on manufacturer websites looking for additional manufacturing information on devices in the academic literature. Snowball searching was also done if any records that were identified appeared relevant [14].

Identified citations were collated using Endnote X8, before uploading to Covidence for de-duplication and screening. Two reviewers (TS and S Huang) independently assessed titles and abstracts of all retrieved citations. For potentially eligible studies, full texts were retrieved and assessed by two independent reviewers (TS and S Huang) according to the eligibility criteria. Disagreements during both stages were resolved either through discussion or consultation with a third reviewer (AW). We also screened all references of included studies to ensure that all eligible studies had been identified. We directly emailed manufacturers where further clarification on technical specification was required.

Data collection, quality assessment and analysis

Data extraction was conducted using a customized spreadsheet, which we pre-tested and refined on four eligible studies. For each included study, we extracted data on the study design, country, setting and sample size, as well as the device characteristics, including weight, dimensions, method and ease of use, environmental durability, connectivity and power source. Additionally, quality assessment of all included studies was done using a Mixed Methods Appraisal Tool (MMAT) [15]. The MMAT, a tool comprised of two screening questions followed by five questions specific to study type. The MMAT was chosen as it allowed for standardized and objective appraisal of methodological quality across multiple different study types. Data extraction and quality assessment were performed by two independent reviewers, with differences resolved through discussion or involving a third reviewer. Findings from the scoping review were reported descriptively.

The UNICEF TPP outlines 34 key criteria across six domains (Fig 1). For each criterion, the TPP specifies an “ideal standard” and “minimum standard”. Using all the information identified for each device, including the initial source as well as further searches for device manuals and other supplementary material, we scored each device on whether each of the 34 TPP criteria was met. Each criteria had a maximum score of two points—whether it met the ideal standard (score of 2), minimum standard (score of 1), or it was not met or we were unable to determine based on lack of information (score of 0). No additional weighting was used (i.e., all criteria had equal weighting). TPP terminology in some criteria such as “child friendly” were defined through consensus amongst the review team, informed by the UNICEF documentation. An overall score was then totaled for each device (i.e., maximum score of 68) and converted to a percentage. A hypothetical perfect device that met the ideal standard for all 34 TPP criteria would score 100%.

Results

We identified 4,470 citations from database searches, and 876 duplicates were removed. Title and abstract screening of the remaining 3,594 unique citations identified 57 potentially eligible studies. After full text review, a total of 20 studies were included (Fig 2). The most common reasons for exclusion were measuring anthropometric outcomes other than height or length (15 studies), including adult populations only (6 studies) or using an ineligible intervention (such as non-portable technology) (13 studies). Three eligible citations were conference abstracts, we attempted to contact the authors for further information without success, and hence used available data from the abstracts only. A number of devices were identified from grey literature searching and reference checks, however there lacked even minimal performance data for comparison against the UNICEF TPP, and hence were not included.

Fig 2. PRISMA flowchart.

Fig 2

Characteristics and quality of included studies

The 20 included studies were published between 1998 and 2022 (Table 1). Twelve studies (60%) were conducted in high-income countries (UK, Germany, USA, Sweden, Canada, Switzerland, Israel, Netherlands) and eight studies (40%) in low-and-middle-income countries (Guatemala, Kenya, Indonesia, China and South Sudan). Prospective validation studies were the most common study design (15 studies, 88%), reporting quantitative data only. These studies varied in quality, rigor, design and methodology. They were compared against an objective set of criteria designed by experts in reliability and agreement investigation in order to directly compare these studies (Appendix 3 in S1 Appendix) [16]. Two studies (12%) used a mixed-methods approach [17, 18]. The conference abstracts also used prospective validation designs. Twelve studies met 100% of the MMAT quality criteria, three studies met 80% of the quality criteria and two studies met only 40% of the quality criteria. We could not complete MMAT assessment for the conference abstracts (Appendix 4 in S1 Appendix).

Table 1. Characteristics of included studies.

Author Year of Publication Country Region Country income level Type of study Population Sample size Setting MMAT Score
Andrews et al [1]
Kessing et al [25]
2019
2020
UK Europe HIC Prospective validation study Neonates <30 weeks gestational age 17 Inpatient medical facility 80%
Bauman et al [21] Bauman et al [7] 2015
2018
Kenya Africa LMIC Prospective validation study Children 1 month– 8 years 77 Educational facilities OR outpatient medical facilities 100%
Baxter et al [35] 2015 Canada Americas HIC Prospective validation study Children 0–18 years 278 Not specified -
Blank et al [32] 2017 Sweden Europe HIC Prospective validation study Children aged 2–18 years 62 Hospital emergency department and inpatient facility -
Bougma et all [26] 2022 Guatemala, Kenya, China Africa, Asia and Americas LMIC Prospective validation study Children 0–59 months 600 Health surveillance system teams 100%
Conkle et al [17, 22] 2018
2019
USA Americas HIC Prospective validation study + mixed methods Children under 5 years 474 Day care OR medical facility OR religious facility 100%
Glock et al [33, 34] 1999 Germany Europe HIC Prospective validation study Children (age not specified) 101 Medical inpatient and outpatient facility 40%
Jefferds et al [18] 2022 Guatemala, Kenya, China Africa, Asia and Americas LMIC Mixed methods Children 0–59 months 1258 caregivers
29 experts & assistants
Health surveillance system teams 100%
Leidman et al [27] 2022 South Sudan Africa LMIC Prospective validation study 6–59 months 539 Health surveillance system teams 100%
Mayol-Kreiser, et al [29] 2015 USA Americas HIC Prospective validation study Children and adults aged 3–80 years 128(25)a Not specified 100%
Orozco et al [24] 2015 Guatemala Americas LMIC Prospective validation study Neonates 29 Hospital inpatient facility -
Penders et al [23] 2015 Netherlands Europe HIC Prospective validation study Children and adolescents aged 2–18 years 54 Hospital outpatient facility 100%
Sokolover et al [19] 2014 Israel Middle East HIC Prospective validation study Neonates 54 Hospital inpatient facility 100%
Syafiq et al [31] Syafiq et al [30] 2013 Indonesia Asia LMIC Prospective validation study Children <2 years 53 Hospital outpatient facility 100%
Watt et al [20] 1998 UK Europe HIC Prospective validation study Children (age not specified) 32 Medical outpatient facility 40%
Wetzel et al [28] 2018 Switzerland Europe HIC Prospective validation study Children 0–13 years 627 Hospital emergency department 80%

HIC = high-income country; LMIC = low-middle income country; MMAT = mixed-methods assessment tool

a 25 individuals in this sample were children <12 years of age

Three studies (15%) included neonates only, two studies (10%) measured length of children <2 years, and three studies (15%) measured height of children >2 years. Twelve studies (60%) measured both height and length of children. Most studies (17 studies, 89%) used trained researchers only to perform measurements. In one study, two senior neonatologists performed the measurements [19], and in another study it was done by parents and team members, though it was not specified whether they received training [20]. Eleven studies (58%) described using formal device training prior to study commencement [1, 7, 17, 18, 2127]. However, only three studies specified the duration or quality of training [18, 26, 27]. These studies all ran multi-day detailed training for all members of the study team.

In five studies (25%) measurements were performed by a single team member [17, 2831]. In five studies (25%) two members of the study team worked together to measure one individual participant [7, 22]. In three studies (15%) the participant cohort was split in two, with a proportion having a single measurer and the other proportion having measurements performed by two or more team members [20, 21, 23]. A further two studies (10%) used two research staff to perform manual measurements but only one staff member for digital measurements [19, 24]. Five studies (25%) did not specify the number of team members used to measure a participant [1, 25, 3235]. Five studies (25%) specifically rotated the order of measurements between the standard and digital devices, four studies (20%) did not rotate and eleven studies (55%) did not specify.

Characteristics of devices and assessment against UNICEF target product profile

Twelve height/length measurement devices were described across the 20 studies (Table 2). These devices included; SCANTIFY, Leica Disto, AutoAnthro, Gulliver, GLM40, Cannon digital camera, unspecified digital camera, P2B2, Optisizer, Coolpix, GLM30 and PePA. Additional devices such as OneGrows and Kiko [36, 37] were found in the grey literature, however there was not an assessment of the device’s reliability and precision so they were not included in the analysis. Eight devices weighed less than 1kg, one device weighed 6kg, and three devices did not have a weight reported. Six devices used digital camera technology (inclusive of 3D imaging), three used laser technology and three used ultrasound technology. Ultrasonic devices used ultrasonic transducers to send and receive ultrasound signals to measure distance. Laser devices worked by sending pulses of laser light, allowing calculation of time and therefore distance for the reflection to return. Cost ranged from approximately USD$45 to USD$2500. Contributing components to this cost included the device itself, software licenses and ancillary devices such as a tablet or smartphone. Notably, none of the devices that had been formally validated in the academic literature were currently commercially marketed explicitly for measuring height/length in people under the age of 18.

Table 2. Device characteristics.

Device Technology used Weight Dimensions Tested for recumbent or standing use Accuracy* Precision** Connectivity Power requirement Digital display Training required? Time needed (sec) Price (USD)
PePA# [35] Laser - - Recumbent and standing - - - - - - 8.4 -
SCANIFY [1, 25] Camera 0.544kg 25x24x3cm Recumbent 1mm - USB Mains power connection needed - Yes 0.1 1490 for device + cost of phone/computer to transfer data to (variable). Software is free with the device.
Leica Disto D2 [7, 21, 41] Laser 0.1kg Headpiece: 3x 36 cm
Leica meter: 11x4x2 cm
Recumbent and standing 1mm - - Battery operated Yes Yes - 179 for device
AutoAnthro System^ [17, 22] Camera (3D imaging) + smartphone/iPad <0.5kg camera + 0.1–0.5kg smart phone/iPad - Recumbent and standing 1mm 77mm WIFI USB rechargeable Yes Yes 68 379 for AutoAnthro software + 300–600 for camera + cost of iPad/phone (dependent on model approx. 800)
AutoAnthro# [26, 27] Camera (3D imaging) + smart phone/iPad 0.1–0.5kg camera + 0.1–0.5kg smart phone or iPad Camera: (version 1: 109 x18 x 24 mm, version 2: 61 mm x 26mm + dimensions of smart phone/iPad Recumbent and standing 30-620mm 40-70mm WIFI USB rechargeable Yes Yes <1 379 for AutoAnthro software + 300–600 for camera + cost of iPad/phone (dependent on model approx. 800)
Gulliver G-100 [34] Ultrasound - - Standing 28mm - - - - - - 665 for device
BOSCH GLM40 [29, 42] Laser 0.527kg Plate11x27.7cm Laser device 5x4.1x2.4cm Standing 3.5mm - - AAA batteries Yes Yes <0.5 74 for device
Canon digital camera [23] Camera 0.755kg 13.9 x 10.4 x 7.9cm Standing 5mm - USB and WIFI Rechargeable battery - Yes - 1427 for software/camera system + computer cost (variable approx. 1000)
Digital camera [19] Camera - - Recumbent 0.2mm - USB USB rechargeable - Yes - -
P2B2D
Prototype-
[30, 31]
Ultrasound 6kg - Recumbent - - - - - Yes - -
Optisizer App [28] Camera 0.185kg 14.4 x 7.7 x 1.3 cm (and 20×20 cm sized tag) Recumbent and standing - - WIFI USB rechargeable Yes - <30 App cost not specified + cost of iPhone/android (variable)
Nikon Coolpix S-3300 camera [24] Camera 0.128kg 9.5 x 5.8 x 1.9 cm Recumbent 22mm - USB USB rechargeable - - - -
BOSCH GLM 30 [32] Laser 0.09kg 10.5 x 4.1 x 2.4cm Recumbent and standing 3mm - - AAA batteries Yes Yes <0.5 74 for device

a Price at time of literature searching, or otherwise based on data sources identified in the review

b not otherwise specified

*mean difference calculated in mm between new device tested and current gold standard measurement device specified in paper

** mean difference calculated in mm between individual measurements (taken by either the same or different users) using the same device

# AutoAnthro version one when tested in a controlled environment

^AutoAnthro version two and three when tested in field

# Pediatric Platform for Anthropometry

Quantitative data on accuracy were available for twelve devices. Nine devices reported this as the mean difference (mm) between a measurement using the digital device versus a standard device, usually a stadiometer or wooden height board. Four devices met the ideal standard for performance, described as a difference of 1mm or less. These were: Lecia DistoD2, Fuel 3D Scantify, AutoAnthro and a digital camera [1, 7, 17, 19, 22]. Two of these were measured in a controlled environment [19, 22] and two were measured in the field [1, 7]. However, when AutoAnthro was retested in field, outside of a controlled environment, the mean difference ranged from 30-620mm, and therefore it no longer met the UNICEF TPP criteria in this context. One device, the BOSCH GLM30, met the UNICEF TPP criteria for minimum standard, reporting a mean difference of 3mm [32]. The remaining four devices, Gulliver G-100 and three non-specified digital cameras reported mean differences ranging from 3.5mm-28mm, not meeting the TPP criteria [20, 33, 34]. A further three devices had studies where Bland-Altman plots or other statistical analyses were used to assess reliability and validity [28, 30, 31]. The novel devices PePA, OptisizerApp and P2B2D were described as reliable and valid compared to standard measurements on the basis of these [28, 30, 35]. However, we could not directly compare these metrics to the UNICEF TPP standards. Kiko, OneGrows and other devices from the grey literature did not provide a formal accuracy assessments [36, 37].

Quantitative data on precision was available for six devices. Only one device, AutoAnthro when tested in the field, reported precision as the mean difference (mm) between measurements using the same device. In this case, the mean difference of 40-77mm did not uphold the ideal UNICEF TPP criteria [26, 27]. The other five devices (Leica Disto D2, Bosch GLM40, P2B2D, cannon digital camera and unspecified digital cameras) as well as AutoAnthro when tested in a controlled environment documented precision using technical errors of measurement (TEM) and Bland-Altman plots [7, 19, 22, 23, 29, 31]. Each of these studies reported the precision of the device to be comparable to that of manual measurements. However, we could not directly compare these metrics to the UNICEF TPP standards. Kiko, OneGrows and other devices from the grey literature did not provide a formal precision assessments [36, 37].

Twelve devices were scored against the 34 criteria of the UNICEF TPP (Appendix 2 in S1 Appendix). Available studies focused mainly on device accuracy, and lacked information on most other TPP criteria. The mean number of TPP criteria assessed was only 10 of the 34. Table 3 illustrates that of the criteria that were able to be assessed, Leica DistoD2 scored highest (41%) on the TPP matching analysis, followed by AutoAnthro in a controlled environment (33%) and GLM30 (32%).

Table 3. Summary of devices scored against the UNICEF target product profile.

Domain Number of criteria (maximum score) * Scantify [1, 25] Leica Disto D2 [7, 21] AutoAnthro * controlled environment [17, 22] Autoanthro * in field [26, 27] Gulliver [34] GLM40 [29] Cannon Digital Camera [23] Digital Camera [19] P2B2 [30] Optisizer [28] Coolpix [4] GLM30 [32] PePA [35]
Score (%) Score (%) Score (%) Score (%) Score (%) Score (%) Score (%) Score (%) Score (%) Score (%) Score (%) Score (%) Score (%)
Operational & functional requirements 11 (22) 5/22 (23%) 10/22 (45%) 10/22 (45%) 10/22 (45%) 5/22 (23%) 7/22 (32%) 7/22 (32%) 7/22 (32%) 5/22 (23%) 8/22 (36%) 7/22 (32%) 8/22 (36%) 6/22 (27%)
Performance requirements 5 (10) 6/10 (60%) 4/10 (40%) 4/10 (40%) 2/10 (20%) 0/10 (0%) 2/10 (20%) 0/10 (0%) 2/10 (20%) 0/10 (0%) 0/10 (0%) 0/10 (0%) 4/10 (40%) 3/10 (30%)
Product requirements 6 (12) 0/12 (0%) 4/12 (33%) 0/12 (0%) 0/12 (0%) 0/12 (0%) 0/12 (0%) 0/12 (0%) 0/12 (0%) 0 / 12 (0%) 0 / 12 (0%) 0/12 (0%) 0/12 (0%) 0/12 (0%)
User requirements 6 (12) 8/12 (66%) 8/12 (67%) 9/12 (75%) 7/12 (58%) 0/12 (0%) 8/12 (67%) 4/12 (33%) 5/12 (42%) 5/12 (42%) 6/12 (50%) 6/12 (50%) 8/12 (67%) 0/12 (0%)
Supply chain requirements 2 (4) 0/4 (0%) 0/4 (0%) 0/4 (0%) 0/4 (0%) 0/4 (0%) 0/4 (0%) 0/4 (0%) 0/4 (0%) 0/4
(0%)
0 / 4 (0%) 0/4 (0%) 0 4 (0%) 0 4 (0%)
Commercialization Requirements 4 (8) 0/8 (0%) 2/8 (25%) 0/8 (0%) 0/8 (0%) 0/8 (0%) 2/8 (25%) 0/8 (0%) 0/8 (0%) 0/8 (0%) 0 / 8 (0%) 0/8 (0%) 2/8 (25%) 0/8 (0%)
All domains 34 (68) 19/68 (28%) 28/68 (41%) 23/68 (33%) 19/68 (28%) 5/68 (7%) 19/68 (28%) 11/68 (16%) 14/68 (21%) 10/68 (15%) 14/68 (21%) 13/68 (19%) 22/68 (32%) 9/68 (13%)

* If the ideal standard is met for a criterion, a score of 2 is awarded. If the minimum standard is met for a criterion, a score of 1 is awarded. If the standard is not met or insufficient data are available to assess the standard, a score of 0 is awarded.

Two studies assessed user experiences [17, 18], both of which looked at AutoAnthro. The studies found that it was at least as acceptable to capture measurements via scan technology as it was with manual measurement, with a ffavorable perception of AutoAnthro predominant, particularly among anthropometrists. Benefits included a more streamlined process, no need for other resources such as recording documents, being simple to learn and time saving. However, there were limitations such as needing a controlled environment and to remove large items of clothing which was particularly problematic in cold countries. Scanning was also slower and less dependable with an uncooperative child due to the requirement for them to stay still for the duration of the scan. This is a potentially high number of children, as it was noted that 30–50% of children were bothered by having height measured.

Discussion

This scoping review identified 12 portable, digital devices for child height/length measurement. However, there are insufficient data publicly available on these devices, and we cannot determine conclusively whether they meet UNICEF’s criteria for the hypothetical ideal device that meets clinical and public health needs. Some devices show promise as they are lightweight, accurate, digital and rechargeable–all of which are key advantages for real-world use. These devices that are accurate, lightweight and digital show high potential for commercialisation and use within clinical and public health settings. The grey literature search highlighted that portable, digital devices are entering the commercial market. Devices such as Kiko and OneGrows are commercially available for child height/length measurement, however there are no performance data available, particularly in relation to their accuracy and precision. More data on all key criteria outlined by the UNICEF TPP would be required before they can be considered for use in formal health programs. Despite this, the existence of these devices suggests that there is not only a need, but perhaps also a demand from individuals and families. None of the devices that have been validated in the academic literature are marketed and available for use for height/length measurement of children.

Many of the devices in the literature were assessed in a controlled environment. It cannot be assumed that their findings in such settings would translate to accurate use in the field, particularly in low- and middle-income countries. For example, while the AutoAnthro device was accurate and precise in a controlled environment, it did not perform well in clinical contexts in LMICs. Real-world factors such as temperature, lighting, power point connections, clothing specifications for scans and child co-operation need to be accounted for in the design of these products. Until these devices are designed with these operational considerations in mind, they are unlikely to succeed on a larger scale in diverse contexts. Furthermore, current cost of digital portable devices is significantly higher than a stadiometer. Additionally, operational requirements of these conventional methods such as stadiometers not requiring a power source can be considered beneficial, particularly in LMICs.

UNICEF have identified that errors with manual height/length measurement using stadiometers occur and are problematic. These errors commonly result from parallax error (i.e. reading measurements from the wrong angle), difficulty reading measurements in poor lighting, and manual data entry errors [38]. These could all be avoided using digital technology. Given that reliable child growth data is essential to good public health programs, we consider digital devices–if accurate and reliable–to be potentially superior. However, current (or new) products require further development, particularly when considering in context use in LMICs. Currently there are no products that meet the complex requirements for in field use in LMICs, meaning stadiometers remain the gold standard.

Recent reviews looking at portable, digital measurement technology for neonates, infants and children have reported similar results. A systematic review by Van Gils et al looked at portable, digital technology for stress-free growth monitoring in preterm infants [39]. Like our review, they found that novel digital technologies show high promise, yet current devices need ongoing refinements and improvements in order to meet gold standard requirements, especially within clinical contexts. Similarly, a narrative review by Neale et al assessed recent innovations in portable height/length measurement devices [40], concluding that manual measurement devices such as measurement mats and portable stadiometers remain the preferred measuring tools until digital equivalents can be shown to be accurate and precise. Our study had a wider search strategy scope allowing for numerous new devices to be found compared to the other reviews. However, similar to these reviews, we identified a large gap in the current digital product market, despite devices showing promise none currently meet the UNICEF TPP criteria for an ideal product.

A strength of this study was the robust research process and methodology. This scoping review was conducted in accordance with a pre-specified protocol that was in line with contemporary methodological guidance [12]. We searched a wide range of sources, including grey literature, performed screening, data extraction and quality assessment in duplicate for quality control. We also performed the matching analysis using a publicly-available standard from a trusted international organization (UNICEF), which was also performed in duplicate to minimize errors. Despite this, some limitations must be acknowledged. During the TPP matching analysis, the reviewers did not test the discussed devices first hand, relying only on the literature for the analysis, limiting the assessment. Given these devices were not directly tested, it was difficulty to extrapolate from the studies the likely added difficulties in measuring length of young children lying down and how this affected device usage. The search strategy, in particular the choice of databases, provided a large scope addressing a wide array of literature. However, we must acknowledge that the not extending the search into other databases beyond Medline, Embase, CINAHL and Global Health means that certain devices could have been missed. Likewise, multiple different combinations of synonyms in our grey literature search found a diversity of results, however we must also acknowledge that reviewing only the first 50 hits would mean that some devices could have been missed. We were unable to locate additional information for two conference abstracts, meaning we could not fully assess the quality of these studies or their capacity to meet the TPP. It is possible that there is further information pertaining to the 12 identified devices that might have improved (or changed) their TPP matching scores, though these data may not be publicly available for commercial or intellectual property reasons. We tried to mitigate this possible bias through exhaustive searching and contacting manufacturers directly for additional information, though it is still possible that some relevant data were not obtained. The conclusions of the TPP matching analysis will likely change as new information or new devices are developed further. Additionally, it must be noted that many studies were written prior to the TPP publication in 2017, making it plausible that these studies may not have considered some specifications desired by the TPP, impacting the devices overall score.

This review highlights a significant gap in both the current literature and commercial market for devices that measure height/length in children. The matching analysis demonstrates both the potential, as well as key areas for improvement, of current devices. Many devices currently available remain at the prototype or early development stage and have not been adapted for in field use or commercialization. We consider it unlikely that UNICEF’s TPP will currently be fulfilled based on available devices. Despite this, some devices show high potential and reflection of their current status and the industry needs documented in the UNICEF TPP must be reviewed with further research. While further research investment on the most promising devices is warranted, development of novel devices or technologies remains worthwhile. Developers should transparently report the accuracy, precision and reliability of their devices, as well as clearly stating their operational, performance and user requirements. There is a clear impetus to accelerate the development and commercialization of growth measurement devices, to improve nutritional surveillance of children globally.

Conclusions

This review identified a large gap in the academic literature and product market for portable digital growth measurement devices. Although some devices show promise further research is needed to test the validity of these devices in varying contexts. Continued development and commercialization will be important to improve reliability and validity of these devices for widespread use. Further studies are required to identify and develop devices that meet the UNICEF TPP criteria for height/length measurement devices.

Supporting information

S1 Checklist. Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist.

(DOCX)

S1 Appendix. Contains Appendices 1–5.

(DOCX)

Acknowledgments

We gratefully acknowledge Lorena Romero who developed the search strategy.

Data Availability

All relevant data are within the manuscript and its Supporting Information files.

Funding Statement

The authors received no specific funding for this work.

References

  • 1.Andrews ET, Ashton JJ, Pearson F, Beattie RM, Johnson MJ. Handheld 3D scanning as a minimally invasive measuring technique for neonatal anthropometry. Clinical nutrition ESPEN. 2019;33:279–82. doi: 10.1016/j.clnesp.2019.06.012 [DOI] [PubMed] [Google Scholar]
  • 2.Stunting, wasting, overweight and underweight [Website]. Geneva: World Health Organisation; [updated 2023; cited 2022 23rd January 2023]. Available from: https://apps.who.int/nutrition/landscape/help.aspx?menu=0&helpid=391&lang=EN.
  • 3.unicef. Height/Length Measurement Devices Project. 2019. [Google Scholar]
  • 4.WHO. Malnutrition [Web Page]. Geneva: World Health Organisation; 2021. [updated 2022; cited 2022 3rd March 2023]. Available from: https://www.who.int/health-topics/malnutrition#tab=tab_1. [Google Scholar]
  • 5.Department of Nutrition for Health and Development WHO. Global Nutrition Targets 2025: Stunting Policy Brief. Geneva: World Health Organisation; 2014. [Google Scholar]
  • 6.WHO. Obesity and Overweight [Web Page]. Geneva: World Health Organisation; 2021. [updated 9th June 2021; cited 2022 3rd March 2022]. Available from: https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight. [Google Scholar]
  • 7.Bauman A, Ernst K, Hayden M, Roe DJ, Murray R, Agawo M, et al. Assessing community health: An innovative tool for measuring height and length. Journal of tropical pediatrics. 2018;64(2):146–50. doi: 10.1093/tropej/fmx046 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.UNICEF. Evaluation of Innovation in UNICEF Work. Case Study: Height/Length Measurement Devices Project. Report. New York: UNICEF; 2019. November 2019. Report No.: 1. [Google Scholar]
  • 9.UNICEF. UNICEF Target Product Profile Height/length Measurement Device(s). Report. New York: United Nations Children’s Fund, Unit USDI; 2017; October 2017. [Google Scholar]
  • 10.McDougall ARA HR, Goldstein M, Tuttle A, Tong S, Ammerdorffer A, Gülmezoglü AM et al. Systematic evaluation of the preeclampsia drugs, dietary supplements and biologicals pipeline using target product profiles. BMC Med, Accepted. 2022. doi: 10.1186/s12916-022-02582-z [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Peters MDJ, Godfrey CM, McInerney P, Munn Z, Tricco AC, Khalil H. Chapter 11: Scoping Reviews (2020 version). 2020. In: JBI Manual for Evidence Synthesis [Internet]. Joanna Briggs Institute. Available from: https://synthesismanual.jbi.global. [Google Scholar]
  • 12.Tricco AC, Lillie E, Zarin W, O’Brien KK, Colquhoun H, Levac D, et al. PRISMA Extension for Scoping Reviews (PRISMA-ScR): Checklist and Explanation. Ann Intern Med. 2018;169(7):467–73. doi: 10.7326/M18-0850 [DOI] [PubMed] [Google Scholar]
  • 13.Takei S, Taketomi S, Torii S, Tojima M, Kaneoka K, Tanaka S. Characteristics of the Kicking Motion in Adolescent Male Soccer Players Who Develop Osgood-Schlatter Disease: A Prospective Study. Orthopaedic Journal of Sports Medicine. 2022;10(3):1–8. doi: 10.1177/23259671221083567 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Hinde S, Spackman E. Bidirectional citation searching to completion: an exploration of literature searching methods. Pharmacoeconomics. 2015;33(1):5–11. doi: 10.1007/s40273-014-0205-3 [DOI] [PubMed] [Google Scholar]
  • 15.Hong QN. Mixed Methods Appraisal Tool (MMAT) Version 2018 User Guide2018 3rd April 2022 [cited 2022 5th May 2022]; 1:[11 p.]. Available from: http://mixedmethodsappraisaltoolpublic.pbworks.com/w/file/fetch/127916259/MMAT_2018_criteria-manual_2018-08-01_ENG.pdf.
  • 16.Kottner J, Audigé L, Brorson S, Donner A, Gajewski BJ, Hróbjartsson A, et al. Guidelines for Reporting Reliability and Agreement Studies (GRRAS) were proposed. Journal of Clinical Epidemiology. 2011;64(1):96–106. doi: 10.1016/j.jclinepi.2010.03.002 [DOI] [PubMed] [Google Scholar]
  • 17.Conkle J, Ramakrishnan U, Martorell R, Suchdev PS, Keirsey K, Hughes A, et al. A collaborative, mixed‐methods evaluation of a low‐cost, handheld 3D imaging system for child anthropometry. Maternal & Child Nutrition. 2019;15(2):N.PAG–N.PAG. doi: 10.1111/mcn.12686 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 18.Jefferds MED, Mei Z, Palmieri M, Mesarina K, Onyango D, Mwando R, et al. Acceptability and Experiences with the Use of 3D Scans to Measure Anthropometry of Young Children in Surveys and Surveillance Systems from the Perspective of Field Teams and Caregivers. Current Developments in Nutrition. 2022;6(6):nzac085. doi: 10.1093/cdn/nzac085 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Sokolover N, Phillip M, Sirota L, Potruch A, Kiryati N, Klinger G, et al. A novel technique for infant length measurement based on stereoscopic vision. Archives of disease in childhood. 2014;99(7):625–8. doi: 10.1136/archdischild-2013-304291 [DOI] [PubMed] [Google Scholar]
  • 20.Watt V, Pickering M, Wales JKH, Wales JK. A comparison of ultrasonic and mechanical stadiometry. Archives of Disease in Childhood. 1998;78(3):269–70. doi: 10.1136/adc.78.3.269 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Bauman A EK, Taren D. Assessing community health: Innovation in anthropometric tool for measuring height and length. Annals of Global Health. 2015;81(1):187–8. [Google Scholar]
  • 22.Conkle J, Suchdev PS, Alexander E, Flores-Ayala R, Ramakrishnan U, Martorell R. Accuracy and reliability of a low-cost, handheld 3D imaging system for child anthropometry. PloS one. 2018;13(10):e0205320. doi: 10.1371/journal.pone.0205320 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Penders B, Brecheisen R, Gerver A, van Zonneveld G, Gerver W-J. Validating Paediatric Morphometrics: body proportion measurement using photogrammetric anthropometry. Journal of Pediatric Endocrinology and Metabolism. 2015;28(11–12):1357–62. doi: 10.1515/jpem-2015-0172 [DOI] [PubMed] [Google Scholar]
  • 24.Orozco M SA, Noel S. The validity of digital-camera photography for estimating birth-length in Guatemalan newborns. FASEB (Meeting Abstracts). 2017;29(1). [Google Scholar]
  • 25.Kessing R. Anthropometric measurements of preterm infants with a 3D scanner. Aktuelle Ernahrungsmedizin. 2020;45(1):6. [Google Scholar]
  • 26.Bougma K, Mei Z, Palmieri M, Onyango D, Liu J, Mesarina K, et al. Accuracy of a handheld 3D imaging system for child anthropometric measurements in population-based household surveys and surveillance platforms: an effectiveness validation study in Guatemala, Kenya, and China. American Journal of Clinical Nutrition. 2022;116(1):97–110. doi: 10.1093/ajcn/nqac064 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Leidman E, Jatoi MA, Bollemeijer I, Majer J, Doocy S. Accuracy of Fully Automated 3D Imaging System for Child Anthropometry in a Low-Resource Setting: Effectiveness Evaluation in Malakal, South Sudan. JMIR Biomed Eng. 2022;7(2):e40066. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 28.Wetzel O, Schmidt AR, Seiler M, Scaramuzza D, Seifert B, Spahn DR, et al. A smartphone application to determine body length for body weight estimation in children: a prospective clinical trial. Journal of clinical monitoring and computing. 2018;32(3):571–8. doi: 10.1007/s10877-017-0041-z [DOI] [PubMed] [Google Scholar]
  • 29.Mayol-Kreiser SN, Garcia-Turner VM, Johnston CS. Examining the utility of a laser device for measuring height in free-living adults and children. Nutrition journal. 2015;14:93. doi: 10.1186/s12937-015-0082-4 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.Syafiq A, Fikawati S. Reliability and validity test of digital infant length measurement board with sonar sensor precision. Malaysian Journal of Nutrition. 2013;19:303–9. [Google Scholar]
  • 31.Syafiq A FS. Innovation on development, reliability and validity test of digital infant length measurer with sonar sensor precision. 20th International Congress of Nutrition; 15-20th September 2013; Granada, Spain2013. p. 1437. [Google Scholar]
  • 32.Blank C DN, Finkel Y. A handheld laser device to measure standing height and supine length in children. NUTRITION: Clinical nutrition; May 2017; Prague: The European Society for Paediatric Gastroenterology, Hepatology and Nutrition; 2017. p. 856. [Google Scholar]
  • 33.Glock F, Vogel M, Naumann S, Kuehnapfel A, Scholz M, Hiemisch A, et al. Validity and intraobserver reliability of three-dimensional scanning compared with conventional anthropometry for children and adolescents from a population-based cohort study. Pediatric Research. 2017;81(5):736–44. doi: 10.1038/pr.2016.274 [DOI] [PubMed] [Google Scholar]
  • 34.Glock M, Hartmann KKP, Hermanussen M, Keller E. Gulliver G-100—A new device to evaluate daily growth measurement in comparison with Harpenden stadiometer. Hormone Research. 1999;52(6):287–90. doi: 10.1159/000023497 [DOI] [PubMed] [Google Scholar]
  • 35.al Be. Measuring Child Length and Height: Assessing the Accuracy of a Portable Infrared-based Digital Tool. FASEB Journal. 2015;31(3). [Google Scholar]
  • 36.OneGrows. One Grows: Length/Height Measurer [Web Page]. Australia: OneGrows; 2021. [updated 2022; cited 2022 3rd March 2022]. Available from: https://www.littleonesgrow.com.au/. [Google Scholar]
  • 37.MagpieTech. Kiko [Wed Page]. Seoul: Magpie Tech Inc; 2022. [cited 2022 3rd March 2022]. 1:[Available from: https://www.heykiko.com/. [Google Scholar]
  • 38.UNICEF. Height/length Measurement Device: UNICEF; 2022. [cited 2022 18th June 2022]. Available from: https://www.unicef.org/innovation/heightlength-measurement-device. [Google Scholar]
  • 39.van Gils RHJ, Wauben L, Helder OK. Body size measuring techniques enabling stress-free growth monitoring of extreme preterm infants inside incubators: A systematic review. PLoS One. 2022;17(4):e0267285. doi: 10.1371/journal.pone.0267285 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40.Neale G, Gaihre S, O’Gorman P, Price RK, Balzategi AG, Barrientos CH, et al. Review of recent innovations in portable child growth measurement devices for use in low- and middle-income countries. Journal of Medical Engineering and Technology. 2021;45(8):642–55. doi: 10.1080/03091902.2021.1946181 [DOI] [PubMed] [Google Scholar]
  • 41.Leica. Leica DISTO D2 User Manual [Web Page]. LeicaGeosystems; 2022. [cited 2022 7th May 2022]. Available from: https://shop.leica-geosystems.com/sites/default/files/2019-03/leica_disto-d2_user-manual_838725_837031_en.pdf. [Google Scholar]
  • 42.BOSCH. GLM 40 Professional [Web Page]. Robert Bosch Power Tools; 2021. [updated 2021; cited 2022 4th March]. Available from: https://www.bosch-pt.com.au/au/en/products/glm-40-0601072980. [Google Scholar]

Decision Letter 0

Alexandra Schaefer

12 Jan 2023

PONE-D-22-30401

Portable digital devices for child height and length measurement: a scoping review and target product profile matching analysis

PLOS ONE

Dear Dr. Soller,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Feb 26 2023 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Alex Schaefer, PhD

Associate Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at 

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and 

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Please complete a PRISMA-ScR checklist (available at https://www.equator-network.org/wp-content/uploads/2018/09/PRISMA-ScR-Fillable-Checklist-1.docx) and upload it as supplementary file.

3. Thank you for stating the following financial disclosure: 

  "This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. JPV is supported by a NHMRC Investigator Grant. All authors declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work; no other relationships or activities that could appear to have influenced the submitted work."

At this time, please address the following queries:

a) Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution. 

b) State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”

c) If any authors received a salary from any of your funders, please state which authors and which funders.

d) If you did not receive any funding for this study, please state: “The authors received no specific funding for this work.”

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

4. Please ensure that you include a title page within your main document. You should list all authors and all affiliations as per our author instructions and clearly indicate the corresponding author.

5. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information. 

Additional Editor Comments:

The reviewers feel that the literature search of this review needs to be updated since the search performed in the current version of the manuscript was done almost one year ago. The reviewers also note that the methodology and discussion need revisions. 

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: N/A

Reviewer #3: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This is a timely, interesting, and well written paper. Please check text for minor typos (e.g., line 109, the should be they).

Going through the list of devices outlined in Table 2, most seem to be repurposed digital/laser measuring devices. Some were discontinued and no longer available. A quick search indicates that a person or object's height can be measured with an iPhone. I am not an expert in this specific technology, but I do work in digital app development and my sense is that the field today is far ahead of the technology outlined in the table. Free or low-cost smartphone apps are now available for quantifying numerous body dimensions, although perhaps such software has not been designed for use in young children; but that would be trivial advance.

While I think the authors have done a good job reviewing the available literature, am I right that the digital world has or can move far beyond repurposed digital tape measures for evaluating children's length or height?

Reviewer #2: This manuscript is an important contribution to the overall quality of the children's anthropometric data collection. However, we would like to suggest some major revisions:

1. Expend the scope of the literature review up to Dec 2022. Some important articles were recently published and are not included in this review as the authors limited their search to almost 1 year ago (18 January 2022). Few examples:

Bougma et al., American Journal of Clinical Nutrition. 2022 Jul 6;116(1):97-110. doi: 10.1093/ajcn/nqac064.

Jefferds et al., Current Development in Nutrition. 2022 Apr 19;6(6). doi: 10.1093/cdn/nzac085.

Leidman et al., JMIR Biomed Eng 2022;7(2): e40066 doi:10.2196/40066

2. On the performance requirement of the UNICEF TPP, lease have separate section of precision besides the accuracy section included. Include a precision column in Table 2. Also add the term accuracy to the * for mean difference

3. Please nuance the main conclusion about some devices meeting the criteria for accuracy as most were validated in controlled setting. Please refer to the suggested articles in point one. The performance was not consistent in other settings

4. Cost of devices: Please consider the cost of acquisition of the data for the devices not providing directly/immediately the results. See the example of Auto Anthro. Also, considerer the cost recurrent licensing.

5. Performance requirements: please provide details on each device regarding "Immediate results"

6. References: Please review and reformat all the reference section

Minor comments:

Introduction

Line 89: include length-for-age also in the definition of stunting, not only height-for-age.

Line 91: include weight-for-length in the definition of wasting, not only weight-for-height

L91: I am not sure that obesity as defined by weight-for age z-score is a ration.

L110: Could you specify what you mean by "inconvenient' to use

Methods:

Line 148: typo. Please proofread all the manuscript

L163: See major comment. Update the scope of the literature review

L244: typo

Figure 1: please specify "screened by title and abstract

Results:

- See major comment for inclusion of separate section on precision.

- Please be specific on the terms used. Clarify what performance is related to ... accuracy or precision or both and be specific when talking about accuracy versus precision. Do not pull them together under terms like performance.

Reviewer #3: Overall comments

This study aimed to conduct a scoping review to identify and evaluate portable digital devices that are currently available to assess length and height measurement in children and adolescents <18 years of age. This is an interesting study and informative to understand the current landscape of digital portable devices available for anthropometric measurements. However, there are several key components of the methods are unclear and the interpretation of the findings does not take into account that the evidence from low- and middle-income countries is very little, which warrant discussion and tempering the conclusion in the abstract. I have made several comments below to strengthen the clarity of the methods and interpretation of the results.

Major comments

Introduction

o Please clarify how stadiometers or length boards are considered “inconvenient to use”. Many in the field, particularly those working in low- and middle-income country context would consider stadiometers and length boards are the most pragmatic tools to measure height and length. Clarity around how these tools are inconvenient and how digital tools might be 'simple to use' in any given context with varying levels experience with technological devises among users would be important.

Methods

Study design – please provide a table listing the UNICEF TPP criteria within the study design component of the methods as this is a key component of this study methodology and design. The study design without the specificity of what these 34 criteria are appears incomplete to the reader.

Literature search –

� I am surprised that some of the large and interdisciplinary databases, e.g., Pubmed, Web of Science, and Scopus – were not searched as these databases are likely to index most of the public health and clinical literature relevant to this review. Would the authors please clarify the rationale? Including such a rationale in the limitations section, I expect, would be warranted.

� Please cite Appendix 2 in the text to clarify that the search terms are detailed in the supplementary material.

o Lines 186-187: Please provide additional details regarding the Mixed Methods Appraisal Tool for clarity. It is unclear what this tool entails and how it is similar or different from other tools of quality assessment.

o Line 191: Please provide the UNICEF TPP Box 1 earlier, in the study design section for clarify.

o Please include either pragmatic definitions of how each criteria in UNICEF TPP Box 1 was operationalized for scoring or use-case examples for scoring each component. It is unclear from the current description, for example, how “long storage life” or “long operational life” or “operates across wide ranging climatic conditions” were systematically scored.

Results:

o Lines 220-221: Please provide additional details regarding the validation designs used in each study. The types of validations and the rigor of validation can vary substantially between studies, therefore such detail will be useful to interpret the utility of these tools. I recommend a table format for clarity (I see that further details are provided in the subsequent two paragraphs generalizing the validation exercises under taken but it is not clear to me which device validation was completed with which design).

o Please also provide additional details regarding the results for the MMAT score – a table in the appendix score each study against the MMAT criteria will be important for clarity.

Discussion:

o Majority of the studies found were developed and validate for use in high-income countries, and only 5 studies, tested in only 3 low- and middle-income countries, that tested the validity of digital portable anthropometry tools. This is a major gap and the very little evidence and development of tools in LMICs suggest that much work is needed here and that the technological barriers post by digital tools, which were not necessarily created with LMIC contexts in mind, certainly do not outweigh the benefits of tools such as the stadiometer. This warrants further comment in the discussion section (i.e. the utility of such tools that have very minimal evidence or validation in LMIC).

Abstract

o I find the conclusion of the abstract is overstated as the three devises – Leica DistoD2, Authoanthro, and GLM30 – all fail at least one of the UNICEF TPP minimum criteria. As a result, I suggest that no device names be used in the conclusion of the abstract. Rather, I suggest a more balanced and cautious interpretation of the data in the last sentence as follows: “Although some devices show promise, further research is needed to test the validity of these devices in varying contexts, and continued development and commercialization will be important to improve reliability of these devices for widespread use.”

Minor comments

Introduction

- Please use the definitions of <-2 standard deviations from the reference median when describing stunting and wasting for accuracy and clarity (rather than “low”).

- Eligibility criteria section: please clarify why the year 1992 was chosen specifically as the start year for searching for relevant articles.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: Yes: Karim Bougma

Reviewer #3: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PLoS One. 2023 Jul 26;18(7):e0288995. doi: 10.1371/journal.pone.0288995.r002

Author response to Decision Letter 0


1 Mar 2023

As per the document 'response to reviewers'

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

Response: We have amended the manuscript to meet attached style guidelines

2. Please complete a PRISMA-ScR checklist (available at https://www.equator-network.org/wp-content/uploads/2018/09/PRISMA-ScR-Fillable-Checklist-1.docx) and upload it as supplementary file.

Response: We have attached the completed checklist as a supplementary file

3. Thank you for stating the following financial disclosure:

"This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. JPV is supported by a NHMRC Investigator Grant. All authors declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work; no other relationships or activities that could appear to have influenced the submitted work."

At this time, please address the following queries:

a) Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution.

b) State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”

c) If any authors received a salary from any of your funders, please state which authors and which funders.

d) If you did not receive any funding for this study, please state: “The authors received no specific funding for this work.”

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

Response: Amended statement as follows

This research received no specific grant, sources of funding or material support from any agency in the public, commercial or not-for-profit sectors. The research was supported by the Burnet Institute, however there was no funding received from this institution. JPV is supported by a NHMRC Investigator Grant. Funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. All authors declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work; no other relationships or activities that could appear to have influenced the submitted work.

4. Please ensure that you include a title page within your main document. You should list all authors and all affiliations as per our author instructions and clearly indicate the corresponding author.

Response: We have amended the manuscript accordingly

5. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information.

Response: We have amended the manuscript accordingly

Additional Editor Comments:

The reviewers feel that the literature search of this review needs to be updated since the search performed in the current version of the manuscript was done almost one year ago. The reviewers also note that the methodology and discussion need revisions.

Response: Thank you for your advice regarding expanding the scope of the literature review. We re ran the search on the 2nd Feb 2023. We have updated the results and discussion accordingly. There were three additional quality papers added. These provided valuable data on the use of portable height/length measurement devices infield, especially in low- and middle-income countries. One of these studies also added depth though including analysis of user perceptions/experiences when using these devices.

One additional systematic review was also found through the search. This was van Gils, R. H. J., Wauben, L. S. G. L., & Helder, O. K. (2022). Body size measuring techniques enabling stress-free growth monitoring of extreme preterm infants inside incubators: A systematic review. PloS one, 17(4), e0267285. https://doi.org/10.1371/journal.pone.0267285. While this was not directly included in the analysis, the review provided a valuable reference point for comparison and analysis in our discussion. The comparatively significant number of papers published on this topic in 2022 not only enhances our scoping review but also suggests that now is a pertinent time to publish such as review as research into this topic is accelerating.

Please see direct responses to reviewers’ comments about methodology and discussion below.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Partly

Response: Noted, thanks. Please see direct response to comments/revisions.

________________________________________

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: N/A

Reviewer #3: Yes

Response: Noted, thanks.

________________________________________

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Response: Noted, thanks.

________________________________________

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Response: Noted, thanks.

________________________________________

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This is a timely, interesting, and well written paper. Please check text for minor typos (e.g., line 109, the should be they).

Going through the list of devices outlined in Table 2, most seem to be repurposed digital/laser measuring devices. Some were discontinued and no longer available. A quick search indicates that a person or object's height can be measured with an iPhone. I am not an expert in this specific technology, but I do work in digital app development and my sense is that the field today is far ahead of the technology outlined in the table. Free or low-cost smartphone apps are now available for quantifying numerous body dimensions, although perhaps such software has not been designed for use in young children; but that would be trivial advance.

While I think the authors have done a good job reviewing the available literature, am I right that the digital world has or can move far beyond repurposed digital tape measures for evaluating children's length or height?

Response: Thank you for taking the time to review this manuscript. It is really valuable to have your perspective as an app developer. As a team of multidisciplinary health care professionals and researchers the perspective you are able to provide is extremely valuable to the translatability and usefulness of this review to industry and product development.

In response to your comments:

We have reviewed for minor typos and corrected the typo on line 109 accordingly.

We also found a number of devices in the grey literatures including apps which could be used to measure body dimensions. However, none of these devices were formally validated to ensure accuracy and precision when used in the paediatric population. While we are not app developers, we agree that this must be a trivial advance to current technology. UNICEF has highlighted the need for technological innovation in height measurement since the target product profile for such devices was released in 2017. We hope this review will highlight this gap, creating an impetus to accelerate advances and promote developers to translate technical improvements seen in other areas to improve measurement and nutritional surveillance of children globally.

Reviewer #2: This manuscript is an important contribution to the overall quality of the children's anthropometric data collection. However, we would like to suggest some major revisions:

Thank you for taking the time to review this manuscript. As an anthropometry specialist with decades of experience your insights and opinions are extremely valuable. You have provided very sound feedback that we feel has greatly enhanced and strengthened our review, so thank you for all the thought and consideration you put into writing it. We have addressed individual comments below.

1. Expend the scope of the literature review up to Dec 2022. Some important articles were recently published and are not included in this review as the authors limited their search to almost 1 year ago (18 January 2022). Few examples:

Bougma et al., American Journal of Clinical Nutrition. 2022 Jul 6;116(1):97-110. doi: 10.1093/ajcn/nqac064.

Jefferds et al., Current Development in Nutrition. 2022 Apr 19;6(6). doi: 10.1093/cdn/nzac085.

Leidman et al., JMIR Biomed Eng 2022;7(2): e40066 doi:10.2196/40066

Response: Thank you for your advice regarding expanding the scope of the literature review. We re ran the search on the 2nd Feb 2023. We have updated the results and discussion accordingly. In this search we have included the papers suggested above. These provided valuable data on the use of portable height/length measurement devices infield, especially in low- and middle-income countries (LMIC). This in field research is particularly important to ensure that the academic literature is translatable to real world clinical application. This was an area that was not thoroughly discussed prior to inclusion of these papers. Hence expanding the dates of this review added significant depth to the quality of our manuscript. One of these studies also added depth though including analysis of user perceptions/experiences, another important aspect to consider in order to allow for industry transition that was lacking in our prior analysis.

One additional systematic review was also found through the search. This was van Gils, R. H. J., Wauben, L. S. G. L., & Helder, O. K. (2022). Body size measuring techniques enabling stress-free growth monitoring of extreme preterm infants inside incubators: A systematic review. PloS one, 17(4), e0267285. https://doi.org/10.1371/journal.pone.0267285. While this was not directly included in the analysis, the review provided a valuable reference point for comparison and analysis in our discussion.

The comparatively significant number of papers published on this topic in 2022 not only enhances our scoping review but also suggests that now is a pertinent time to publish such a review as research into this topic has accelerated over the last 12 months.

2. On the performance requirement of the UNICEF TPP, lease have separate section of precision besides the accuracy section included. Include a precision column in Table 2. Also add the term accuracy to the * for mean difference

Response: Thank you for addressing this. While we thoroughly addressed accuracy, we agree that precision is a very important aspect that was a significant gap in our earlier manuscript.

We have included a paragraph on precision following the accuracy section of our results. We have copied it here for your reference:

Quantitative data on precision was available for six devices. Only one device, AutoAnthro when tested in the field, reported precision as the mean difference (mm) between measurements using the same device. In this case, the mean difference of 40-77mm did not uphold the ideal UNICEF TPP criteria (23, 24). The other five devices (Leica Disto D2, Bosch GLM40, P2B2D, cannon digital camera and unspecified digital cameras) as well as AutoAnthro when tested in a controlled environment documented precision using technical errors of measurement (TEM) and Bland-Altman plots (6, 16, 19, 20, 26, 28). Each of these studies reported the precision of the device to be comparable to that of manual measurements. However, we could not directly compare these metrics to the UNICEF TPP standards. Kiko, OneGrows and other devices from the grey literature did not provide a formal precision assessments (32, 33).

We have also updated Table 2 with a column on precision and added the term accuracy as specified above. We have also included precision as a key focus point in our discussion.

3. Please nuance the main conclusion about some devices meeting the criteria for accuracy as most were validated in controlled setting. Please refer to the suggested articles in point one. The performance was not consistent in other settings

Response: Thank you for this advice, we have nuanced the conclusion accordingly. Key changes show that while some devices show promise it is important that devices are designed with purpose and validated within the context that they will be used.

We have copied the conclusion here for your reference:

This review identified a large gap in the academic literature and product market for portable digital growth measurement devices. Although some devices show promise further research is needed to test the validity of these devices in varying contexts. Continued development and commercialization will be important to improve reliability and validity of these devices for widespread use. Further studies are required to identify and develop devices that meet the UNICEF TPP criteria for height/length measurement devices.

4. Cost of devices: Please consider the cost of acquisition of the data for the devices not providing directly/immediately the results. See the example of Auto Anthro. Also, considerer the cost recurrent licensing.

Response: Thank you for this suggestion, this is an important consideration when assessing the cost of such devices. We have updated the results, Table 2 and our discussion accordingly.

5. Performance requirements: please provide details on each device regarding "Immediate results"

Response: Thank you for prompting us to clarify this, we have updated Table 2 and our results accordingly. Each device (where data was available) now has a specific time for results listed in seconds. For reference we have defined immediate results as any result taking less than 1 second to process.

6. References: Please review and reformat all the reference section

Response: Noted, and references have been reviewed and reformatted according to PLOS ONE guidelines.

Minor comments:

Introduction

Line 89: include length-for-age also in the definition of stunting, not only height-for-age.

Response: Amended accordingly.

Line 91: include weight-for-length in the definition of wasting, not only weight-for-height

Response: Amended accordingly.

L91: I am not sure that obesity as defined by weight-for age z-score is a ration.

Response: We have amended the definition to match that published by the WHO.

Definition is copied here for reference. Obesity: a body mass index greater than 3 standard deviations above the WHO growth standard median.

L110: Could you specify what you mean by "inconvenient' to use

Response: Thank you for allowing us to clear up ambiguity around this statement. We have recreated this paragraph to clarify perceived limitations with manual anthropometry. We have copied this paragraph here for your reference:

Measurement boards (stadiometers) are currently the gold-standard tool for obtaining child height and length, including in community-based child health surveillance activities (6). While they have been in widespread use for decades, they are cumbersome and heavy.(7) The process of manual data collection also increases the risk of transcription errors, negatively affecting data accuracy.

Methods:

Line 148: typo. Please proofread all the manuscript

Response: Amended accordingly. We have also proof read the manuscript for other typos.

L163: See major comment. Update the scope of the literature review

Response: Please see response to major comment above. We have amended the dates in the methodology to match this revision.

L244: typo

Response: Amended accordingly. We have also proof read the manuscript for other typos.

Figure 1: please specify "screened by title and abstract

Response: Amended accordingly.

Results:

- See major comment for inclusion of separate section on precision.

Response: Please see response to major comment above.

- Please be specific on the terms used. Clarify what performance is related to ... accuracy or precision or both and be specific when talking about accuracy versus precision. Do not pull them together under terms like performance.

Response: Thank you for flagging this important issue. By adding analysis on precision to our results and discussion we were able to highlight the importance of both accuracy and precision to the performance of height/length measurement devices. We also made sure we clearly differentiated between accuracy and precision, ensuring that they were no longer pooled into a single entity.

Reviewer #3: Overall comments

This study aimed to conduct a scoping review to identify and evaluate portable digital devices that are currently available to assess length and height measurement in children and adolescents <18 years of age. This is an interesting study and informative to understand the current landscape of digital portable devices available for anthropometric measurements. However, there are several key components of the methods are unclear and the interpretation of the findings does not take into account that the evidence from low- and middle-income countries is very little, which warrant discussion and tempering the conclusion in the abstract. I have made several comments below to strengthen the clarity of the methods and interpretation of the results.

Thank you for taking the time to review this manuscript. You have provided well thought through feedback that we feel has greatly improved and strengthened our review. We found it particularly valuable reflecting on the translatability of these findings to LMICs, where accurate nutritional surveillance of children is paramount. We have addressed individual comments below.

Major comments

Introduction

o Please clarify how stadiometers or length boards are considered “inconvenient to use”. Many in the field, particularly those working in low- and middle-income country context would consider stadiometers and length boards are the most pragmatic tools to measure height and length. Clarity around how these tools are inconvenient and how digital tools might be 'simple to use' in any given context with varying levels experience with technological devises among users would be important.

Response: Thank you for allowing us to clear up ambiguity around this statement. We have recreated this paragraph to clarify perceived limitations with manual anthropometry and possible advantages of digitalisation. We have copied this paragraph here for your reference:

Measurement boards (stadiometers) are currently the gold-standard tool for obtaining child height and length, including in community-based child health surveillance activities (6). While they have been in widespread use for decades, they are cumbersome and heavy.(7) The process of manual data collection also increases the risk of transcription errors, negatively affecting data accuracy. A digital, accurate measurement device would thus provide significant advantages for clinical assessment and nutritional surveillance of children. If such a device were portable, lightweight, and reliable, with simple data storage and transfer abilities, it would make child health assessments easier. This is especially pertinent in resource-limited settings, where the large, cumbersome measurement board can be particularly difficult to transport and use, and reliable data transcription and record-keeping can be challenging.

Methods

Study design – please provide a table listing the UNICEF TPP criteria within the study design component of the methods as this is a key component of this study methodology and design. The study design without the specificity of what these 34 criteria are appears incomplete to the reader.

Response: Thank you for flagging this important issue. We have listed the UNICEF TPP criteria as Figure 1 in the study design section of the methodology. We have also greatly improved this figure by listing in detail a pragmatic definition of how each criterion was defined in our study. These definitions are based directly off the UNCIEF TPP.

Literature search –

� I am surprised that some of the large and interdisciplinary databases, e.g., Pubmed, Web of Science, and Scopus – were not searched as these databases are likely to index most of the public health and clinical literature relevant to this review. Would the authors please clarify the rationale? Including such a rationale in the limitations section, I expect, would be warranted.

Response: We agree that this is an important consideration which as a team we thoroughly reviewed before commencing our search. We decided on the use of Medline, Embase, CINAHL and Global Health databases following exploratory searches across multiple databases and consultation with an information specialist. We also thoroughly cross-checked the references of all papers and systemic or narrative reviews we found in order to ensure that we were not missing any important papers. While we feel that the search was thorough and allowed us to evaluate the most up to date literature on the topic, we do acknowledge the limitations provided by our choice of data bases which we have added to the limitations section of the discussion.

� Please cite Appendix 2 in the text to clarify that the search terms are detailed in the supplementary material.

Response: Amended accordingly.

o Lines 186-187: Please provide additional details regarding the Mixed Methods Appraisal Tool for clarity. It is unclear what this tool entails and how it is similar or different from other tools of quality assessment.

Response: We have added a sentence to clarify what the MMAT tool is. We have copied the sentence here for your reference.

The MMAT, a tool comprised of two screening questions followed by five questions specific to study type. The MMAT was chosen as it allows for a standardized and objective appraisal of methodological quality across multiple different study types.

Further details as to how the MMAT tool is best utilised can be found in the MMAT user guide from MgGill University (reference 14): Hong QN. Mixed Methods Appraisal Tool (MMAT) Version 2018 User Guide2018 3rd April 2022 [cited 2022 5th May 2022]; 1:[11 p.]. Available from: http://mixedmethodsappraisaltoolpublic.pbworks.com/w/file/fetch/127916259/MMAT_2018_criteria-manual_2018-08-01_ENG.pdf.

o Line 191: Please provide the UNICEF TPP Box 1 earlier, in the study design section for clarify.

Response: Amended accordingly, please see comment above.

o Please include either pragmatic definitions of how each criteria in UNICEF TPP Box 1 was operationalized for scoring or use-case examples for scoring each component. It is unclear from the current description, for example, how “long storage life” or “long operational life” or “operates across wide ranging climatic conditions” were systematically scored.

Response: Amended accordingly, each criterion now has a pragmatic and practical definition based directly off the UNICEF TPP. Please see Figure 1 for details.

Results:

o Lines 220-221: Please provide additional details regarding the validation designs used in each study. The types of validations and the rigor of validation can vary substantially between studies, therefore such detail will be useful to interpret the utility of these tools. I recommend a table format for clarity (I see that further details are provided in the subsequent two paragraphs generalizing the validation exercises under taken but it is not clear to me which device validation was completed with which design).

Response: We have created a table (Appendix 2) which directly compares all studies using validation designs. These were compared for rigor, methodolgy and quality using a methodological criterion created by experts in reliability and agreement investigation (reference for this methodology: Kottner J, Audigé L, Brorson S, Donner A, Gajewski BJ, Hróbjartsson A, et al. Guidelines for Reporting Reliability and Agreement Studies (GRRAS) were proposed. Journal of Clinical Epidemiology. 2011;64(1):96-106.)

o Please also provide additional details regarding the results for the MMAT score – a table in the appendix score each study against the MMAT criteria will be important for clarity.

Response: We have created a table (Appendix 3) with the results for each component of the MMAT score for each study. This should create clarity around results.

Discussion:

o Majority of the studies found were developed and validate for use in high-income countries, and only 5 studies, tested in only 3 low- and middle-income countries, that tested the validity of digital portable anthropometry tools. This is a major gap and the very little evidence and development of tools in LMICs suggest that much work is needed here and that the technological barriers post by digital tools, which were not necessarily created with LMIC contexts in mind, certainly do not outweigh the benefits of tools such as the stadiometer. This warrants further comment in the discussion section (i.e. the utility of such tools that have very minimal evidence or validation in LMIC).

Response: Thank you for this insightful comment. Expanding the dates of the literature search to include an additional 3 papers looking at height/length measurement devices in LMIC contexts reinforces your view. These studies demonstrated that while devices such as AutoAnthro have been validated in controlled environments in high income countries this does not translate when tested in the field in LMICs. This review demonstrates that there is currently a significant design and knowledge gap for translational research within these contexts. This has been addressed in our ammedments to the discussion which we hope creates an impetus for future studies that focus on specific requirements for use in LMICs.

We have coppied some ammendments here for your reference:

For example, while the AutoAnthro device was accurate and precise in a controlled environment, it did not perform well in a study in clinical contexts in LMICs. Real-world factors such as temperature, lighting, power point connections, clothing specifications for scans and child co-operation need to be accounted for in the design of these products. Until these devices are designed with these operational considerations in mind, they are unlikely to succeed on a larger scale in diverse contexts.

…..

Given that reliable child growth data is essential to good public health programs, we consider digital devices – if accurate and reliable – to be potentially superior. However, current (or new) products require further development, particularly when considering in context use in LMICs. Currently there are no products that meet the complex requirements for in field use in LMICs, meaning stadiometers remain the gold standard.

Abstract

o I find the conclusion of the abstract is overstated as the three devises – Leica DistoD2, Authoanthro, and GLM30 – all fail at least one of the UNICEF TPP minimum criteria. As a result, I suggest that no device names be used in the conclusion of the abstract. Rather, I suggest a more balanced and cautious interpretation of the data in the last sentence as follows: “Although some devices show promise, further research is needed to test the validity of these devices in varying contexts, and continued development and commercialization will be important to improve reliability of these devices for widespread use.”

Response: We have amended the conclusion of the study to be more balanced and cautious as you have outlined above.

We have copied the new abstract conclusion here for your reference:

While 11 portable, digital devices exist for child height/length measurement, insufficient data are available to fully assess whether they meet the industry’s needs. Although some devices show promise, further research is needed to test the validity of these devices in varying contexts, and continued development and commercialization will be important to improve reliability of these devices for widespread use.

Minor comments

Introduction

- Please use the definitions of <-2 standard deviations from the reference median when describing stunting and wasting for accuracy and clarity (rather than “low”).

Response: We have amended this accordingly. All definitions are written as standard deviations from the reference median as per the WHO definition.

We have copied the amendments here for your reference:

Stunting, defined as more than two standard deviations below the median height-for-age/length-for-age, affects approximately 162 million children under 5 years worldwide.

……

Wasting is defined as more than two standard deviations below the median weight-for-height/weight-for-length and indicates recent and severe weight loss.

- Eligibility criteria section: please clarify why the year 1992 was chosen specifically as the start year for searching for relevant articles.

Response: Thank you for this question as we feel that this is an important consideration. As a team this is something we thought deeply about. We searched the literature from 1 January 1992 onwards, which captured 30 years of data. We did this as we believe that 30 years of data would allow for a thorough evaluation of all contemporary product as well as giving us insight into how this has changed over time. We acknowledge that most of the relevant data is from the last decade. However, feel that 30 years of data gave us a good idea of how this field has changed and evolved over time – providing a useful perspective for the review.

Attachment

Submitted filename: response to reviewers.docx

Decision Letter 1

Nandita Perumal

30 May 2023

PONE-D-22-30401R1

Portable digital devices for child height and length measurement: a scoping review and target product profile matching analysis

PLOS ONE

Dear Dr. Soller,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

While Reviewer #1 has generally provided positive comments and finds the manuscript suitable for publication, Reviewer #4 raised several queries. I understand that it may not be possible to re-run the systematic search; however, I urge the authors to address the careful critiques provided by Reviewer #4 for greater clarity in the methods and results, and further reflections in the discussion, and revise the manuscript accordingly.   

Please submit your revised manuscript by Jul 14 2023 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Nandita Perumal, PhD

Guest Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #4: (No Response)

********** 

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #4: Partly

********** 

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #4: N/A

********** 

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #4: Yes

********** 

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #4: Yes

********** 

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have made all of my suggested revisions. I have no additional comments. This is a useful review on this topic.

Reviewer #4: Thank you for the opportunity to review this scoping review on different portable tools to measure child height and length. The current work describes studies identified through published and grey literature, and how they compare to the UNICEF TPP. Measuring child height and length objectively and with high validity is important, making this an interesting assessment. Enclosed, please find several queries to the authors with the intention of strengthening the manuscript.

Methods:

- The search was last conducted >1 year ago (Jan 2022). The researchers should consider re-running the search strategy.

- The search strategy is noted in Appendix, but this does not appear in Methods text. Reference to the corresponding Appendix should be added.

- From reviewing the search strategy, was infant or child length searched? It seems the preference was for height, although the term used for those <2 years is typically length, and child length is noted in the Title of the manuscript.

- In the grey literature searches (Google), why were the first 50 hits considered only? Is there a reference or methodology that supports this approach? Given that Google has strong algorithms that control what a searcher might observe, do the researchers believe this figure is appropriately representative of the tools available?

- Would it be possible to indicate which reviewers conducted the reviews and which reviewer was approached for consultation?

Results:

- Since the Abstract and Discussion note that 13 portable devices were identified, this should appear within the Results section. It can be determined by counting Table 2, but only that 16 studies were identified is mentioned in the Results. A sentence stating 13 portable devices would improve the manuscript clarity.

- To assess the UNICEFF TPP, it seems that several characteristics (e.g., cost) go beyond those mentioned as part of in the customized data extraction form. How were these characteristics captured?

- Had the researchers come across the following study in their searches?

Additional study:

Baxter, J.-A., Roth, D., Zlotkin, S., Yin, S., Milgram, P. and Mouzaki, M. (2015), Measuring Child Length and Height: Assessing the Accuracy of a Portable Infrared-based Digital Tool. The FASEB Journal, 29: 31.3. https://doi.org/10.1096/fasebj.29.1_supplement.31.3

- For completeness, the researchers should consider adding a simple table to the Appendix that lists the articles excluded and reasons for exclusion. These studies may be of interest to the readership.

Discussion:

- Line 284-85: Per above, it is noted that 13 portable devices were identified. This had not previously been noted in the Results, only the number of studies. Suggest adding number of unique devices within the results, as 16 studies is mentioned, and determining that there are 13 devices requires counting lines in the table.

- The Neale et al study is introduced in line 310, but then 2 sentences from line 311-16 (starting with UNICEF have identified...) appear before mention of Neale again. Are these 2 sentences supposed to appear here? They seem out of place. As well, being clear about how the methods/scope of the current review is different from Neale would improve the interpretability.

- Based on the UNICEF TPP findings and last few paragraphs of the Results, could the researchers provide further critical reflection in the Discussion about the practicality of tools available, if they were to be used in diverse settings? (i.e., LMICs) A good portion of space in the Introduction reflects on stunting and wasting, and which are conditions more likely to affect those in LMICs. Do these devices seem practical for use in LMICs? For example, could reflect on cost relative to existing standard tools (could look at seca or Harpenden for cost comparison) or power requirements (standard length and height boards do not currently require a power source).

- Could the researchers reflect further on the limitations of their own study methods as conducted?

(1) Given this is a review of the literature, the researchers likely didn't interact with any of the tools themselves. In other words, without ever seeing the tools, and just reading text, do the reviewers feel that they were adequately able to assess TPP characteristics? Comparing reports of some characteristics in the UNICEFF TPP could be subjective, especially given comparison is being made between studies.

(2) Measuring length and height is quite different, length is conventionally much more difficult to measure - largely related to the age of the child and their cooperation whilst being measured. There is information on length versus height in the Results, so this could be further reflected upon.

(3) As the UNICEF TPP was published in 2017 and several identified studies were published before this, it is quite plausible that they would not report on such characteristics. This could be reflected on further.

Appendix:

- The Tables presented in the Appendix do not align with the main manuscript (Table 1 in the Appendix is noted as Table 3 in text).

- Search strategy is provided in the Appendix, but not listed in the main paper. Within the Appendix, given the placement of mention of the search strategy, this should appear first (i.e., before UNICEF TPP)

- A table describing exclusions at full-text stage would strengthen the manuscript, and is standard practice for other review platforms

********** 

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #4: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PLoS One. 2023 Jul 26;18(7):e0288995. doi: 10.1371/journal.pone.0288995.r004

Author response to Decision Letter 1


21 Jun 2023

Dear Dr Perumal,

Many thanks for your response. We appreciate the time and thought taken to rereview our manuscript. The reviewers have provided valuable feedback which we feel has strengthened our manuscript.

Regards,

Tasmyn, on behalf of the study team

Response to reviewers:

Reviewer #1: The authors have made all of my suggested revisions. I have no additional comments. This is a useful review on this topic.

Response: Thank you.

Reviewer #4: Thank you for the opportunity to review this scoping review on different portable tools to measure child height and length. The current work describes studies identified through published and grey literature, and how they compare to the UNICEF TPP. Measuring child height and length objectively and with high validity is important, making this an interesting assessment. Enclosed, please find several queries to the authors with the intention of strengthening the manuscript.

Response: Thank you for your comments. Please find detailed responses below and accompanying revisions in the manuscript.

Methods:

The search was last conducted >1 year ago (Jan 2022). The researchers should consider re-running the search strategy.

Response:

As per the methods (Page 7), the search was re-run on the 2 February 2023 to ensure the most up-to-date papers were included.

The search strategy is noted in Appendix, but this does not appear in Methods text. Reference to the corresponding Appendix should be added.

Response: we have now referenced the corresponding appendix in the methods.

From reviewing the search strategy, was infant or child length searched? It seems the preference was for height, although the term used for those <2 years is typically length, and child length is noted in the Title of the manuscript.

Response: Thank you for raising this, height and length terminology was comprehensively considered in the development of our search strategy. We are aware that height is measured standing in children >2 years and length is measured lying down for infants <2 years old and we carefully selected available terminology to reflect this in our search. This is demonstrated in our results whereby most studies measured length of children < 2 years, 5 of which exclusively measured length – suggesting this was adequately addressed in the search strategy. Please find these results described as follows:

“Three studies (16%) included neonates only, two studies (11%) measured length of children <2 years, and three studies (16%) measured height of children >2 years. Eleven studies (58%) measured both height and length of children”

In the grey literature searches (Google), why were the first 50 hits considered only? Is there a reference or methodology that supports this approach? Given that Google has strong algorithms that control what a searcher might observe, do the researchers believe this figure is appropriately representative of the tools available?

Response: Thank you for raising this, we acknowledge that searching google can be overwhelming due to the abundance of information. We are also aware that google search engines use relevancy rankings to bring the most pertinent results to the top.

Our search was run in incognito mode with location and trending searches turned off. Our methodology was initially tested using a number pilot run whereby multiple team members searched the grey literature until hits no longer became relevant to the research question. During this pilot it was felt that the first 50 hits captured most of the relevant websites. Furthermore we ran multiple different grey literature searches using different combinations of synonyms which allowed us to adequately capture a breath of resources. We also used snowball searching if any records were identified to be relevant.

We have expanded on this in the methodology as follows: “We also used Google searches to identify any height/length measurement devices that were commercially available at the time of searching. These were run in incognito mode, with location and trending searches turned off. These searches used various combinations of structured search terms and synonyms similar to the formal literature search, and we inspected the first 50 hits. Targeted searches were also conducted on manufacturer websites looking for additional manufacturing information on devices in the academic literature. Snowball searching was also done if any records that were identified appeared relevant.”

We do however acknowledge that this approach comes with limitations and as such have included an additional section in our discussion to highlight this “multiple different combinations of synonyms in our grey literature search found a diversity of results, however we must also acknowledge that reviewing only the first 50 hits would mean that some devices could have been missed”.

Would it be possible to indicate which reviewers conducted the reviews and which reviewer was approached for consultation?

Response: Yes, we have added in the initials of the reviewers as follows:

“Two reviewers (TS and S Huang) independently assessed titles and abstracts of all retrieved citations. For potentially eligible studies, full texts were retrieved and assessed by two independent reviewers (TS and S Huang) according to the eligibility criteria. Disagreements during both stages were resolved either through discussion or consultation with a third reviewer (AW).”

Results:

Since the Abstract and Discussion note that 13 portable devices were identified, this should appear within the Results section. It can be determined by counting Table 2, but only that 16 studies were identified is mentioned in the Results. A sentence stating 13 portable devices would improve the manuscript clarity.

Response: Twelve portable devices were identified, one of which was trialled both in a controlled environment and in the field. An additional sentence stating all these devices has been added to the results, as follows:

“Twelve height/length measurement devices were described across the 20 studies (Table 2). These devices included; SCANTIFY, Leica Disto, AutoAnthro, Gulliver, GLM40, Cannon digital camera, unspecified digital camera, P2B2, Optisizer, Coolpix, GLM30 and PePA”

To assess the UNICEFF TPP, it seems that several characteristics (e.g., cost) go beyond those mentioned as part of in the customized data extraction form. How were these characteristics captured?

Response: Characteristics were captured by directly emailing manufacturers and utilising a grey literature search to look for specifications of devices found in the academic literature. This was described in the methods section as follows:

“We also used Google searches to identify any height/length measurement devices that were commercially available at the time of searching.... Targeted searches were also conducted on manufacturer websites looking for additional manufacturing information on devices in the academic literature. …We directly emailed manufacturers where further clarification on technical specification was required”.

Had the researchers come across the following study in their searches?

Additional study:

Baxter, J.-A., Roth, D., Zlotkin, S., Yin, S., Milgram, P. and Mouzaki, M. (2015), Measuring Child Length and Height: Assessing the Accuracy of a Portable Infrared-based Digital Tool. The FASEB Journal, 29: 31.3. https://doi.org/10.1096/fasebj.29.1_supplement.31.3

Response: Yes, this paper did come up in our initial search findings. It is a conference abstract with no corresponding full paper. At the time we contacted the authors to try and find the complete paper without success. The initial decision was made to exclude it on the basis of very limited information. However on reflection, we have amended the manuscript to include it as an abstract only paper. While it doesn’t add much depth to the paper due to very limited detail, adding it highlights a thorough search strategy, which allowed us to provide a solid and evidenced based review.

For completeness, the researchers should consider adding a simple table to the Appendix that lists the articles excluded and reasons for exclusion. These studies may be of interest to the readership.

Response: please see included as appendix 5

Discussion:

Line 284-85: Per above, it is noted that 13 portable devices were identified. This had not previously been noted in the Results, only the number of studies. Suggest adding number of unique devices within the results, as 16 studies is mentioned, and determining that there are 13 devices requires counting lines in the table.

Response: please see comment above in results section.

The Neale et al study is introduced in line 310, but then 2 sentences from line 311-16 (starting with UNICEF have identified...) appear before mention of Neale again. Are these 2 sentences supposed to appear here? They seem out of place. As well, being clear about how the methods/scope of the current review is different from Neale would improve the interpretability.

Response: Thank you we have outlined how our review differs to Neale et al and have revised for clarity as follows:

“Recent reviews looking at portable, digital measurement technology for neonates, infants and children have reported similar results. A systematic review by Van Gils et al looked at portable, digital technology for stress-free growth monitoring in preterm infants (38). Like our review, they found that novel digital technologies show high promise, yet current devices need ongoing refinements and improvements in order to meet gold standard requirements, especially within clinical contexts. Similarly, a narrative review by Neale et al assessed recent innovations in portable height/length measurement devices (39), concluding that manual measurement devices such as measurement mats and portable stadiometers remain the preferred measuring tools until digital equivalents can be shown to be accurate and precise. Our study had a wider search strategy scope allowing for numerous new devices to be found compared to the other reviews. However, similar to these reviews, we identified a large gap in the current digital product market, despite devices showing promise none currently meet the UNICEF TPP criteria for an ideal product.”

Based on the UNICEF TPP findings and last few paragraphs of the Results, could the researchers provide further critical reflection in the Discussion about the practicality of tools available, if they were to be used in diverse settings? (i.e., LMICs) A good portion of space in the Introduction reflects on stunting and wasting, and which are conditions more likely to affect those in LMICs. Do these devices seem practical for use in LMICs? For example, could reflect on cost relative to existing standard tools (could look at seca or Harpenden for cost comparison) or power requirements (standard length and height boards do not currently require a power source).

Response: Thank you. We touched on this issue in the discussion but have revised for clarity as follows:

“Furthermore, current cost of digital portable devices is significantly higher than a stadiometer. Additionally, operational requirements of these conventional methods such as stadiometers not requiring a power source can be considered beneficial, particularly in LMICs.”

Could the researchers reflect further on the limitations of their own study methods as conducted?

Response: Thank you we have now added further content to the limitations section of our discussion to the points outlined by the reviewer below:

(1) Given this is a review of the literature, the researchers likely didn't interact with any of the tools themselves. In other words, without ever seeing the tools, and just reading text, do the reviewers feel that they were adequately able to assess TPP characteristics? Comparing reports of some characteristics in the UNICEFF TPP could be subjective, especially given comparison is being made between studies.

“During the TPP matching analysis, the reviewers did not test the discussed devices first hand, relying only on the literature for the analysis, limiting the assessment”

(2) Measuring length and height is quite different, length is conventionally much more difficult to measure - largely related to the age of the child and their cooperation whilst being measured. There is information on length versus height in the Results, so this could be further reflected upon.

“Given these devices were not directly tested, it was difficulty to extrapolate from the studies the likely added difficulties in measuring length of young children lying down and how this affected device usage.”

(3) As the UNICEF TPP was published in 2017 and several identified studies were published before this, it is quite plausible that they would not report on such characteristics. This could be reflected on further.

“Additionally, it must be noted that many studies were written prior to the TPP publication in 2017, making it plausible that these studies may not have considered some specifications desired by the TPP, impacting the devices overall score.”

Appendix

The Tables presented in the Appendix do not align with the main manuscript (Table 1 in the Appendix is noted as Table 3 in text).

Response: Amended accordingly. Thank you.

Search strategy is provided in the Appendix, but not listed in the main paper. Within the Appendix, given the placement of mention of the search strategy, this should appear first (i.e., before UNICEF TPP)

Response: Amended accordingly. Thank you.

A table describing exclusions at full-text stage would strengthen the manuscript, and is standard practice for other review platforms

Response: Amended – added as appendix 5.

Attachment

Submitted filename: Response to reviewers_PLOS ONE.docx

Decision Letter 2

Nandita Perumal

10 Jul 2023

Portable digital devices for paediatric height and length measurement: a scoping review and target product profile matching analysis

PONE-D-22-30401R2

Dear Dr. Soller,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Nandita Perumal, PhD

Harvard TH Chan School of Public Health

Guest Editor

PLOS ONE

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #4: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #4: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #4: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #4: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #4: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #4: Thank you to the authors for addressing all items raised. This paper will be of interest to those in the field.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #4: No

**********

Acceptance letter

Nandita Perumal

17 Jul 2023

PONE-D-22-30401R2

Portable digital devices for paediatric height and length measurement: a scoping review and target product profile matching analysis

Dear Dr. Soller:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Nandita Perumal

Guest Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Checklist. Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist.

    (DOCX)

    S1 Appendix. Contains Appendices 1–5.

    (DOCX)

    Attachment

    Submitted filename: response to reviewers.docx

    Attachment

    Submitted filename: Response to reviewers_PLOS ONE.docx

    Data Availability Statement

    All relevant data are within the manuscript and its Supporting Information files.


    Articles from PLOS ONE are provided here courtesy of PLOS

    RESOURCES