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. Author manuscript; available in PMC: 2024 Jun 1.
Published in final edited form as: Autism Res. 2023 Apr 3;16(6):1174–1184. doi: 10.1002/aur.2927

Consistency Between Parent Report and Direct Assessment of Development in Toddlers with ASD and Other Delays: Does Sex Assigned at Birth Matter?

Stephen James 1, Shreyas Hallur 1, Joshua Anbar 2, Nicole Matthews 1, Karen Pierce 3, Christopher J Smith 1
PMCID: PMC10330170  NIHMSID: NIHMS1894076  PMID: 37009713

Abstract

The current study examined differences between parent report and diagnostician direct assessment of receptive language, expressive language, and fine motor abilities in toddlers with autism spectrum disorder (ASD) and other delays. Additionally, this study examined whether parent-diagnostician consistency varied by child diagnosis and sex assigned at birth (SAB). Initial mixed ANOVAs were conducted using data from a sample of 646 toddlers to examine whether parent-diagnostician consistency differed by child diagnosis. Matched samples (using child age, SAB, and nonverbal IQ) were then created within each diagnostic group and mixed ANOVAs were conducted to examine if consistency was similar in matched diagnostic subsamples and whether it differed by SAB. Findings from the full sample mostly replicated previous research that has documented consistency between parent report and direct observation regardless of child diagnosis. However, when examined in matched diagnostic subgroups, more nuanced patterns were observed. Parent report of receptive language was lower in ASD and ASD features subgroups and parent report of fine motor skills was lower than direct observation in the ASD, ASD features, and developmental delay groups. When examining the moderating effect of SAB, only expressive language was impacted for children in the ASD group. Results indicate the importance of considering child demographic characteristics and that child SAB may impact parent report and/or diagnostician perception of expressive language.

Keywords: autism, sex, parent report, direct assessment, toddlers

Lay Summary

Research suggests parents are generally reliable reporters of child development. Little is known, however, about whether reliability of parent report differs by child sex. In this study we found that parents of children with autism rated their child’s language comprehension abilities and fine motor skills differently than professional diagnosticians, and that consistency between parent-report and direct-observation by diagnosticians of expressive language varied by child sex. Our findings suggest child demographics/characteristics should be considered when examining parent report of language production.

Whereas previous research has found that parents of children with autism spectrum disorder (ASD) and other delays are reliable reporters of development in general (Luyster et al., 2008; Miller et al., 2017), no published research to our knowledge has examined if consistency between parent report and direct assessment by diagnostic professionals varies as a function of child sex assigned at birth (SAB). Determining if parent-diagnostician consistency varies by SAB would contribute to a limited but growing understanding of sex and gender differences in ASD and potentially shed light on how child SAB may influence screening and diagnostic efforts. In a large, community-based sample identified through universal developmental screening, the current study examined consistency between parent report and direct assessment of skills and whether consistency varied by child diagnosis and SAB in toddlers with ASD and other delays.

Parent-Report and Direct Observation Assessment Methods

Gold standard assessment methods for ASD include developmental history interviews with parents and direct observation by a diagnostic professional. Both components have advantages and disadvantages. Whereas parents have observed their child’s behaviors across time and in various environments, they may have a limited understanding of typical development and may be prone to bias (Nordahl-Hansen et al., 2014). Conversely, diagnostic professionals have specialized training in child development, but direct testing usually takes place in a confined environment and during a short period of time. Thus, behaviors observed may not be representative of those demonstrated in other more naturalistic settings (Miller et al., 2017). To overcome shortcomings of each approach, a combination of parent report and direct observation is often used.

There is some evidence that, despite their shortcomings, results from widely used parent-report and direct observation measures are consistent. Specifically, Miller and colleagues (2017) examined consistency between the Vineland Adaptive Behavior Scales (VABS; Sparrow et al., 2005) (parent report) and the Mullen Scales of Early Learning (MSEL; Mullen, 1995) (direct testing) across three areas of development: receptive language, expressive language, and fine motor abilities. Results indicated no main effect of assessment type, and no interaction between assessment type and child diagnosis (ASD, developmental delay, typical development), for any of the three areas of development measured. Notably, the comparison of fine motor skills was trending toward significance (p = .051), with parents reporting slightly higher fine motor abilities relative to direct assessment. Despite this, findings suggested consistency between parent report and direct testing of language and fine motor skills regardless of child diagnosis. Furthermore, there was no effect of language in which the evaluation was conducted (English vs. Spanish) or maternal education level on consistency between data source for any of the three areas of development. Interestingly, analyses did not consider or control for variables like child age, SAB, and developmental level. It is possible that both parent report and direct assessment of child abilities may be influenced by child demographics, which suggests the need for additional research that directly examines or controls for these variables. Emerging evidence on sex and gender differences in ASD and the shift toward sex and gender-informed research warrants specific examination of potential sex differences in parent-diagnostician consistency.

Sex Differences in ASD

The most recent CDC report estimates that one in 27 boys, and one in 114 girls, has ASD, which represents a 4.2:1 male-to-female ratio (Maenner et al., 2021). Slightly smaller ratios have been estimated when using other sources of data such as the National Survey of Children’s Health (3.8:1) (Kogan et al., 2018) and the National Health Interview Survey (2.9:1) (Zablotsky et al., 2017). Nonetheless, a male bias in prevalence has consistently been found across data sources, although decreases in the male to female ratio have emerged in recent years due to greater increases in prevalence among girls than boys (Maenner et al., 2021). One factor that may contribute to the increased prevalence among girls is a better understanding of the difference in ASD symptom presentation between males and females (Loomes et al., 2017). The stereotypical belief that ASD is a male disorder is slowly changing as more evidence finds subtle, yet distinct, phenotypic sex differences. In particular, increased attention has focused on the female autism phenotype, which is a female-specific presentation that differs from the more traditional (i.e., male-centered) characterization of the disorder (Hull et al., 2020).

Findings from research that has examined sex differences in social communication and social interaction in children with ASD are somewhat mixed. Whereas comparable social challenges have been observed using conventional tools (e.g., the Autism Diagnostic Observation Schedule (ADOS) (Lord et al., 2012)), differences have been reported when examining specific aspects of social communication and interaction and when using various research methods (Lai & Szatmari, 2020). For example, using eye-tracking procedures to measure visual attention to faces, Harrop and colleagues (2019) found enhanced social attention in females with ASD relative to males with ASD. Other research suggests females with ASD may have better communicative skills, social motivation, and higher quality friendships than their male counterparts (Lai & Szatmari, 2020; Sedgewick et al., 2019). In terms of linguistic abilities, females with ASD tend to be better story tellers, have more internal state language, and have a greater ability to participate in reciprocal conversation than males (Conlon et al., 2019; Hiller et al., 2014, Kauschke et al., 2016). Emerging research, however, suggests that females may appear to have better social communication skills because they engage in ‘camouflaging’ behaviors (Wood-Downie et al., 2021). The “camouflaging hypothesis” posits that individuals with ASD learn and use strategies and compensatory behaviors based on social rules to mask difficulties and to fit into situations (Hull et al., 2020; Livingston & Happe, 2017). Research suggests that females are more likely than males to engage in social masking and compensatory behaviors, especially in high-pressure situations such as clinical assessments (e.g., Dean et al., 2017; Hull, Petrides, & Mandy, 2020; Ormond et al., 2018). This variation in presentation across settings may lead to variation in the perception and report of symptoms by different observers.

The Current Study

The objective of the current study was to build on prior research that has compared parent report and direct testing of development using the VABS and MSEL in a sample of toddlers with ASD and other delays. Although previous studies have found overall consistency between parent report and direct testing of language and fine motor skills, important child demographic variables (e.g., age, developmental level) were not controlled for and the potential moderating effect of child SAB on this relationship has not been examined. The aims of the present study were to:

  1. Replicate previous findings indicating consistency between parent report and direct observation of language and fine motors skills in children with and without ASD. We hypothesized that language and fine motor skills scores would not differ significantly by assessment type in the full sample.

  2. Examine consistency between parent report and direct observation of language and fine motor skills in diagnostic subgroups matched on child age, SAB, and nonverbal IQ, and assess the effect of child SAB on parent-diagnostician consistency. Based on previous research, we hypothesized that language and fine motor skills would not differ by assessment type in the diagnostic subgroups, but we predicted a moderating effect of SAB in light of literature suggesting sex and gender differences in ASD; however, due to an absence of previous research on the interaction between SAB and assessment type, we did not hypothesize directionality of this effect.

Methods

Participants

Participants included 646 toddlers who received developmental evaluations as part of a larger federally-funded project assessing the feasibility of replicating a revised version of the 1-Year Well-Baby Check-Up Approach – the Get SET Early Model – in a new city (see Pierce et al., 2011; Pierce et al., 2021; Smith et al., 2022). The overarching goal of the Get SET Early model was to lower the age of autism diagnosis and treatment starting at the pediatric level. In the parent study, a network of 109 pediatric healthcare professionals (PHPs) from 13 practices were recruited across the Phoenix metropolitan area and trained to implement a structured universal screening and referral procedure (see Smith et al., 2022). PHPs in the network agreed to screen universally at 12-, 18-, and 24-month well-visits using a standardized questionnaire, the Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist (ITC) (Wetherby et al., 2008). Toddlers whose scores fell into the concern range were referred to the study center for a developmental evaluation. Participants also included one parent of each toddler who was evaluated at the study center. Parent participants had to speak English or Spanish. All children who were screened and referred by 36-months of age were eligible to participate in the study. There were no other inclusion/exclusion criteria.

Licensed clinical psychologists conducted all developmental testing and classified each case into one of five diagnostic judgement categories based on the following criteria: (1) ASD – ADOS-2 score in the range of concern and considered ASD based on DSM-5 criteria; (2) ASD Features (ASDf) – participants in this group demonstrated behaviors consistent with autism during the ADOS-2, but they did not meet one or more DSM-5 criteria (i.e., A1-A3; B1-B4; C, D, E; American Psychiatric Association, 2013) based on the licensed psychologist’s clinical judgement; (3) language delay (LD) – MSEL receptive or expressive language or both subscales scores greater than 1 standard deviation below the mean; (4) developmental delay (DD) – two+ MSEL subscale scores greater than 1 standard deviation below the mean (at least one domain outside of the verbal domain), or developmental issues present but not captured in any of the aforementioned categories (e.g., motor delay); and (5) typically developing (TD) – scores on all clinical assessments in the normal range. The study protocol was reviewed and approved by the Institutional Review Board at the University of California, San Diego and informed consent was obtained from at least one parent/guardian of each child.

Two participants from the parent study were excluded from the current study due to missing data on assessments used for diagnostic classification. There were no other exclusion criteria. Thus, participants in the current study included 646 toddlers. This full sample was used to address the first aim of the study (i.e., to assess if parent-diagnostician consistency on language and fine motors skills differed by diagnostic group). To address the second aim, (i.e., to assess if parent-diagnostician consistency on language and fine motors skills differed by child diagnosis, and to determine if SAB moderated parent-diagnostician consistency within each diagnostic group), matched samples were created within each diagnostic group using child age and SAB. To control for potential IQ differences, participants were also matched on nonverbal mental abilities. Participants assigned male at birth (AMAB) and participants assigned female at birth (AFAB) were selected in a 1:1 ratio within each diagnostic group using the Fuzzy command in IBM SPSS (Version 24). Specifically, participants in the AMAB group were matched to participants in the AFAB group using child age (within 1 month) and the child’s MSEL Visual Reception T-score (within 5 points) as a proxy for nonverbal IQ. Nonverbal IQ was used in accordance with previous research indicating that nonverbal IQ is more stable estimate of IQ in young children with ASD (Akshoomoff, 2006). Some previous studies have utilized a nonverbal developmental quotient that includes both visual reception and motor skills to approximate nonverbal IQ. We did not utilize this method and instead relied on visual reception to avoid a confound with the fine motor skills subscale, which is a primary outcome variable in the current study. Descriptive statistics for participant demographic variables are reported in Table 1.

Table 1.

Participant Characteristics by Diagnostic Group

Variable Full Sample (n = 646)
ASD (n = 269) ASDf (n = 91) DD (n = 146) LD (n = 96) TD (n = 44)
Age (mos) at Eval. (M (SD)) 23.83 (6.25) 22.54 (6.49) 20.36 (6.80) 19.50 (5.28) 20.80 (6.92)
Child Gender
 Female (%) 19.70 24.18 34.93 28.13 38.64
 Male (%) 80.30 75.82 65.07 71.87 61.36
Ethnicity
 Hispanic/Latino (%) 35.32 24.17 47.26 31.25 36.36
 Not Hispanic/Latino (%) 61.34 71.43 52.74 67.71 61.36
 Did not report (%) 3.34 4.40 - 1.04 2.28
Race
 Caucasian (%) 65.43 69.23 64.39 66.67 68.18
 African American (%) 5.58 9.89 5.48 - 6.82
 Asian (%) 5.20 2.20 2.05 3.12 4.54
 Other (%) 9.29 5.50 5.48 9.38 6.82
 Did not report (%) 14.50 13.18 22.60 20.83 13.64
MSEL VR T-score (M(SD)) 36.21† (12.55) 45.96 (10.88) 42.40 (11.56) 49.54 (8.16) 55.36 (8.16)
Matched Samples (n = 308)
Variable ASD (n = 100) ASDf (n = 38) DD (n = 94) LD (n = 44) TD (n = 32)
AMAB (n = 50) AFAB (n = 50) AMAB (n = 19) AFAB (n = 19) AMAB (n = 47) AFAB (n = 47) AMAB (n = 22) AFAB (n = 22) AMAB (n = 16) AFAB (n = 16)
Age (mos) at Eval. (M (SD)) 24.34 (6.29) 24.30 (6.30) 20.89 (5.80) 20.74 (5.79) 19.17 (6.89) 19.04 (6.81) 17.18 (3.98) 17.09 (4.15) 19.19 (4.72) 18.56 (6.74)
Ethnicity
 Hispanic/Latino (%) 28.00 34.00 26.32 15.79 46.81 46.81 22.73 36.36 43.75 62.50
 Not Hispanic/Latino (%) 68.00 60.00 68.42 84.21 53.19 53.19 72.73 63.64 50.00 37.50
 Did not report (%) 4.00 6.00 5.26 - - - 4.54 - 6.25 -
Race
 Caucasian (%) 50.00 70.00 73.68 84.21 68.09 68.08 63.63 72.73 81.25 56.25
 African American (%) 10.00 4.00 - - 6.38 4.26 - - 6.25 6.25
 Asian (%) 8.00 6.00 5.26 - - 4.26 - - 6.25 -
 Other (%) 16.00 8.00 10.53 5.26 6.38 - 13.64 4.54 - 18.75
 Did not report (%) 16.00 12.00 10.53 10.53 19.15 23.40 22.73 22.73 6.25 18.75
MSEL VR T-score (M(SD)) 35.50 (10.71) 35.50 (10.56) 46.47 (8.44) 46.58 (7.32) 44.32 (11.60) 44.02 (11.79) 48.91 (7.13) 48.32 (7.11) 56.06 (10.74) 55.88 (9.65)
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Notes: ASD = autism spectrum disorder; ASDf = ASD features (where full DSM-5 ASD criteria were not satisfied); DD = developmental delay in multiple areas without meeting full ASD criteria; LD = language delay; TD = typically developing; MSEL = Mullen Scales of Early Learning; VR = Visual Reception; AMAB = assigned male at birth; AFAB = assigned female at birth.

†

Data missing for three participants.

Measures

Autism Diagnostic Observation Schedule, Second Edition (ADOS-2).

The ADOS-2 is a standardized, semi-structured assessment administered by clinically trained professionals to inform ASD diagnosis (Gotham et al., 2007; Lord et al., 2000, 2012). One of five modules is chosen depending on the age and expressive language of the individual being assessed. Participants were all under the age of 36 months, so only three modules were used: Toddler, Module 1, and Module 2. Results from this assessment informed the psychologists’ clinical diagnostic judgment. All psychologists were research reliable ADOS-2 raters.

Mullen Scales of Early Learning (MSEL).

The MSEL is a standardized assessment that measures cognitive functioning in children younger than 68 months of age (Mullen, 1995). The MSEL assesses developmental functioning across four domains: fine motor, visual reception, expressive language, and receptive language. The MSEL has good internal consistency and strong test-retest reliability and inter-rater reliability (Mullen, 1995). The MSEL yields both T-scores and age equivalency scores in each of the four domains. To allow for comparison with the VABS, and consistent with previous research (Miller et al., 2017), age equivalency scores (in months) are used in the current analysis.

Vineland Adaptive Behavior Scales, Second Edition (VABS-2).

The VABS-2 is a standardized assessment that measures adaptive functioning across five domains: communication, daily living skills, socialization, motor skills, and maladaptive behavior. (Sparrow et al., 2005). The VABS-2, which is completed by parents, can be used to characterize adaptive functioning in individuals from birth to ninety years of age. For young children, the VABS-2 has good inter-rater reliability and strong internal consistency and test-retest reliability (Sparrow et al., 2005). The VABS-2 yields both standard scores and age equivalency scores. To allow for comparison with the MSEL, and consistent with previous research (Miller et al., 2017), age equivalency scores (in months) are used in the current analysis.

Analysis

For the first aim of the study, 2 (data source: VABS/MSEL) by 5 (diagnostic group: ASD, ASDf, DD, LD, and TD) mixed ANOVAs were conducted using data from the larger sample (n = 646) to assess parent-diagnostician consistency and whether consistency differed by diagnostic group. Separate mixed ANOVAs were run for expressive language, receptive language, and fine motor abilities using age equivalent scores on the MSEL and VABS corresponding subscales. Due to violations of the homogeneity of variance assumption and unequal diagnostic group sizes, robust ANOVA strategies were used (Mair & Wilcox, 2020) and pairwise comparisons were examined using non-parametric procedures.

For the second aim, matched samples were created using child age, SAB, and nonverbal IQ in each diagnostic group (ASD, n = 100; ASDf, n = 38; DD, n = 94; LD, n = 44; TD, n = 32). Matching samples in this way controlled for variance introduced by child demographic variables. Mixed ANOVAs were conducted for each group to assess if parent-diagnostician consistency on language and fine motors skills differed by child SAB. Similar to the procedures used to address the first aim, separate 2 (data source; VABS/MSEL) by 2 (sex: AMAB/AFAB) mixed ANOVAS were run for expressive language, receptive language, and fine motor abilities using age equivalent scores on the MSEL and VABS corresponding subscales. For all ANOVAs, Bonferroni corrections were applied to pairwise comparisons. To minimize Type I errors associated with testing multiple outcomes in each model, all omnibus tests for ANOVA’s were corrected using Bonferroni-adjustments (i.e., uncorrected omnibus p-values were multiplied by the number of outcomes (3) in each model).

Results

Aim 1

Receptive language scores.

In the full sample (n = 646), a significant main effect of diagnostic group emerged (F(4, 94) = 29.31, p = .003). Specifically, receptive language scores were significantly lower for children in the ASD group than for children in each of the other groups (all ps < .001; see Table 2). Results revealed no significant main effect of assessment type and no significant interaction between assessment type and diagnostic group.

Table 2.

Mean Between-Group Differences in Age-Equivalent Scores for the Full Sample (n = 646)

Receptive Language Expressive Language Fine Motor Skills
Group 1 Group 2 MD p value† Cohen’s d MD p value Cohen’s d MD p value Cohen’s d
ASD ASD Feat. −5.80 <.001 0.78 −3.24 <.001 0.49 −1.28 .53 0.27
DD −2.76 <.001 0.41 −1.31 .006 0.21 1.29 .017 0.27
LD −4.97 <.001 0.72 −0.89 .02 0.15 −0.72 1.00 0.15
TD −10.33 <.001 1.37 −9.04 <.001 1.30 −2.66 .30 0.52
ASDf DD 3.04 .140 0.43 1.93 .50 0.31 2.57 <.001 0.53
LD 0.83 1.00 0.11 2.35 .89 0.43 0.56 1.00 0.12
TD −4.53 .043 0.51 −5.80 .002 0.76 −1.38 1.00 0.24
DD LD −2.21 .074 0.36 0.42 1.00 0.08 −2.01 .008 0.43
TD −7.57 <.001 1.07 −7.73 <.001 1.16 −3.95 .001 0.74
LD TD −5.36 .059 0.71 −8.15 <.001 1.35 −1.94 1.00 0.36
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Notes: MD = mean difference; ASD = autism spectrum disorder; ASDf. = ASD features (where full DSM-5 ASD criteria were not satisfied); DD = developmental delay in multiple areas without meeting full ASD criteria; LD = language delay; TD = typically developing.

†

= Significance after Bonferroni adjustment

Expressive language scores.

A significant main effect of diagnostic group on expressive language scores was observed (F(4, 198) = 17.47, p = .003) such that scores were significantly lower for children in the ASD group than for those in the ASDf (p < .001, d = 0.49), DD (p = .006, d = 0.21), LD (p = .02, d = 0.15) and TD (p < .001, d = 1.30) groups. Results revealed no significant main effect of assessment type and no significant interaction between assessment type and diagnostic group.

Fine motor scores.

There was a significant main effect of diagnostic group on fine motor skills, F(4, 107) = 3.75, p = .018, where children in the ASD group had significantly higher scores than children in the DD group (p = .017, d = 0.27). Neither a significant main effect of assessment type nor a significant interaction between assessment type and diagnostic group was observed.

Aim 2

Receptive language scores.

When examining data from the matched diagnostic subsamples (see Table 3) a significant main effect of assessment type on receptive language scores emerged for children in the ASD group, F(1, 97) = 14.13, p = .003, and for children in the ASDf group, F(1, 36) = 18.24, p = .003. For children in the ASD group, VABS scores (m = 9.52) were significantly lower than MSEL scores (m = 11.91) (p < .001, d = 0.38). Similarly, for children in the ASDf group, VABS scores (m = 13.95) were significantly lower than MSEL scores (m = 17.66) (p < .001, d = 0.71). There was no significant main effect of SAB, and no significant interaction between assessment type and SAB, for any group for receptive language scores.

Table 3.

Mean MSEL and VABS Age-Equivalent Scores in Months by Diagnostic Group

Full Sample (n = 646)
Variable ASD (n = 269) (M(SD)) ASDf (n = 91) (M(SD)) DD (n = 146) (M(SD)) LD (n = 96) (M(SD)) TD (n = 44) (M(SD))
RL
MSEL 11.88† (7.83) 17.86 (8.28) 14.69‡ (6.94) 16.51 (7.01) 21.66 (7.97)
VABS 10.27† (7.53) 15.90 (10.08) 12.99‡ (6.20) 15.59 (7.02) 21.16 (12.59)
MD 1.61*** 1.96* 1.70*** 0.92 0.50
EL
MSEL 12.27 (6.94) 15.26 (6.80) 13.32† (5.64) 12.58 (4.47) 20.43 (7.41)
VABS 11.75 (6.68) 15.23 (7.18) 13.33† (6.20) 13.21 (4.20) 21.66 (11.49)
MD 0.52 0.03 −0.01 −0.63 −1.23
FM
MSEL 18.69§ (4.86) 20.31† (5.01) 18.27† (4.73) 19.41† (4.37) 21.43 (6.90)
VABS 17.88§ (5.56) 18.80† (5.82) 15.71† (5.46) 18.59† (5.63) 20.45 (7.70)
MD 0.81* 1.51** 2.56*** 0.82 0.98
Matched Samples (n = 308)
Variable ASD (n = 100) (M(SD)) ASDf (n = 38) (M(SD)) DD (n = 94) (M(SD)) LD (n = 44) (M(SD)) TD (n = 32) (M(SD))
AMAB (n = 50) AFAB (n = 50) MD AMAB (n = 19) AFAB (n = 19) MD AMAB (n = 47) AFAB (n = 47) MD AMAB (n = 22) AFAB (n = 22) MD AMAB (n = 16) AFAB (n = 16) MD
RL
MSEL 11.58 (6.75) 12.24† (7.34) −0.66 16.47 (8.30) 18.84 (8.02) −2.37 15.38 (8.89) 14.50† (8.51) 0.88 13.14 (4.82) 15.41 (6.93) −2.27 19.63 (5.29) 19.50 (8.13) 0.13
VABS 10.12 (6.30) 8.92† (5.75) 1.20 12.58 (9.52) 15.32 (7.78) −2.74 14.17 (10.02) 13.22† (8.77) 0.95 12.50 (4.09) 16.05 (6.74) −3.55* 18.44 (5.61) 18.50 (11.14) −0.06
MD 1.46 3.32*** 3.89** 3.52** 1.21 1.28 0.64 −0.64 1.19 1.00
EL
MSEL 11.20 (6.08) 12.80 (6.32) −1.60 12.95 (3.64) 15.53 (6.79) −2.58 14.06 (8.97) 14.30 (7.38) −0.24 11.59 (4.02) 12.00 (3.45) −0.41 18.88 (5.41) 18.38 (7.58) 0.50
VABS 12.28 (6.14) 11.56 (6.02) 0.72 12.11 (5.67) 15.68 (6.80) −3.57 14.21 (9.67) 14.53 (9.23) −0.32 10.95 (3.05) 13.59 (3.23) −2.64* 18.19 (5.12) 18.63 (8.58) −0.44
MD −1.08* 1.24* 0.84 −0.15 −0.15 −0.23 0.64 −1.59* 0.69 −0.25
FM
MSEL 18.98 (4.80) 18.94 (3.68) 0.04 19.05 (3.66) 19.47 (4.95) −0.42 18.06 (4.92) 18.32 (7.17) −0.26 17.50 (2.74) 18.18 (3.88) −0.68 20.13 (4.03) 19.19 (7.34) 0.94
VABS 18.10 (5.14) 17.54 (4.31) 0.56 17.05 (4.58) 17.89 (5.58) −0.84 15.96 (7.23) 16.23 (8.51) −0.27 16.50 (4.24) 16.91 (4.45) −0.41 19.06 (4.51) 18.13 (7.77) 0.93
MD 0.88 1.40* 2.00* 1.58* 2.10** 2.09** 1.00 1.27 1.07 1.06
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Notes: RL = receptive language; EL = expressive language; FM = fine motor; MD = mean difference; MSEL = Mullen Scales of Early Learning; VABS = Vineland Adaptive Behavior Scale; ASD = autism spectrum disorder; ASDf = ASD features (where full DSM-5 ASD criteria were not satisfied); DD = developmental delay in multiple areas without meeting full ASD criteria; LD = language delay; TD = typically developing, AMAB = assigned male at birth; AFAB = assigned female at birth

†

Data missing for one participant

‡

Data missing for two participants

§

Data missing for three participants.

*

p < .05

**

p < .01

***

p < .001 (Bonferroni-adjusted significance tests used for pairwise comparisons).

Expressive language scores.

There was no significant main effect of either assessment type or SAB on expressive language scores. However, a significant assessment type by SAB interaction was identified for children in the ASD group, F(1, 98) = 9.84, p = .006. Specifically, VABS scores (m = 11.56) were significantly lower than MSEL scores (m = 12.80) in the AFAB group (p = .02, d = 0.31), whereas VABS scores (m = 12.28) were significantly higher than MSEL scores (m = 11.20) (p = .042, d = 0.33) in the AMAB group.

Fine motor scores.

A significant main effect of assessment type on fine motor skills emerged for children in the ASD (F (1, 98) = 6.40, p = .039), ASDf (F (1, 36) = 11.21, p = .006), and DD (F (1, 92) = 21.27, p = .003) groups. Specifically, VABS scores were significantly lower than MSEL scores for children in the ASD (mVABS = 17.82 vs. mMSEL = 18.96, p = .013, d = 0.26), ASDf (mVABS = 17.47 vs. mMSEL = 19.26, p = .002, d = 0.56), and DD (mVABS = 16.10 vs. mMSEL = 18.19, p < .001, d = 0.52) groups. There was no significant main effect of SAB, and no significant interaction between assessment type and SAB, for any group for fine motor skills.

Discussion

With a sample that is approximately five times larger than previous published work in this area, the current study extends and enhances validity of previous findings indicating consistency between parent report and direct assessment of specific skill sets in children with and without ASD. Further, this study is the first to our knowledge to examine whether parent-diagnostician consistency differs by child SAB. Interesting and potentially clinically relevant patterns of differences by SAB emerged in the receptive and expressive language domains. With replication, findings may inform clinical interpretation of two assessments that are widely used to inform diagnosis, support needs, and progress in children with ASD and developmental delays.

In addressing the first aim, analysis of parent-diagnostician consistency using the full sample replicated findings from prior literature (Luyster et al., 2008, Miller et al., 2017; Nordahl-Hansen et al., 2014). Specifically, results indicated alignment between parent report and direct assessment on receptive language, expressive language, and fine motor skills. Also consistent with previous research (Miller et al., 2017), children in the ASD group were found to have lower language skills than children in other groups.

Analyses addressing the second aim yielded different results using diagnostic subsamples matched on SAB, age, and nonverbal IQ. A significant main effect of assessment type on fine motor skills scores was observed in the ASD, ASDf, and DD subgroups such that parent report scores were significantly lower than direct assessment scores with effect sizes ranging from small to medium depending on diagnostic group. These findings are inconsistent with Miller and colleagues (2017) who observed no significant difference between parent report and direct assessment scores for fine motor skills in their sample, although their results trended towards significance in the opposite direction (p = .051), with parents potentially reporting better fine motor skills than direct assessment. These mixed findings may be due in part to variance introduced by child demographic variables that were not controlled for in statistical analyses by Miller and colleagues (2017). Indeed, within the matched samples in the current study, differences between the two measures were more pronounced (see Table 2). Moreover, investigation of the matched samples also revealed a pattern of underreporting of receptive language skills by parents in the ASD and ASDf groups, relative to direct testing, with small to medium effect sizes. These differences were not found for the LD, DD, and TD groups, which suggests that autism characteristics may uniquely affect reliability between parent report and direct observation of receptive language.

Results suggest parent report of expressive language skills is generally reliable with direct observation by trained diagnosticians, whereas parent report and direct observation of receptive language and fine motor skills is less consistent. This likely reflects the notion that expressive language is more tangible than other developmental milestones to both parents and professionals, making assessment of expressive language more objective. In contrast, receptive language and fine motor skills may be more nuanced and less objective, resulting in reduced reliability between parent-report and direct assessment. One possible explanation is that children more explicitly demonstrate language comprehension when prompted in a formal testing environment. At home, compliance or attentional issues may interfere with a child’s response to requests, or children may not have had the opportunity to demonstrate a skill. As a result, parent report may be less favorable for assessing a child’s receptive language because they see less direct behavioral evidence. When asked whether their child “recognizes 3+ body parts” or “follows 2-step instructions,” parents may respond negatively because they have not observed their child successfully respond. When an examiner asks a child to demonstrate these skills, and the child complies, it leads to a more favorable receptive language score. Importantly, demonstrating a skill during a professional assessment does not necessarily indicate that a child will do the same in their natural environment.

Current findings did not indicate a significant impact of child SAB on receptive or expressive language skills or consistency between parent report and direct assessment of receptive language skills. Despite overall consistency between parent report and direct observation of expressive language, a significant interaction effect was observed such that consistency between parent report and direct assessment of expressive language skills differed by SAB for children in the ASD group. Specifically, parents of children in the ASD AFAB group significantly underreported skills relative to direct observation, whereas parents of children in the ASD AMAB group significantly overreported skills. Although not the focus of their study, a similar trend was reported by Reinhardt and colleagues (2015): expressive language scores on the MSEL were higher for female toddlers with ASD, whereas the VABS Communication domain score was higher for male toddlers with ASD. This pattern of results may suggest that children with ASD who were AMAB are less likely to use language with strangers (e.g., examiners) and in unfamiliar places (e.g., the clinical setting) than they are with more familiar people (e.g., parents) and in more natural environments (e.g., the home). On the other hand, children with ASD who were AFAB are more socially motivated (Lai & Szatmari, 2020; Sedgewick et al., 2019). During testing, children who were AFAB may be likely to engage in unconscious social mimicry with strangers and to mask their autism by employing “typical sounding” communicative tools. Such normalizing behaviors may artificially inflate an unfamiliar observer’s rating of language use. Finally, it is possible that parents of children with ASD may have different expressive language expectations based on the child’s sex. Children with ASD who were AFAB are less represented in popular media and in the general population, given the 4:1 sex ratio in autism diagnosis. Without any representative benchmarks to contextualize the female manifestation of autism, parents may not be able to appropriately gauge their daughters’ development. It is possible that parents of children with autism who were AFAB have inflated expectations based on typically developing children who were AFAB and thus under report expressive language skills. The notion that parent-report and direct observation appear to be consistent in the full sample but are indeed statistically different and follow contrasting patterns across sexes highlights the need to study potential sex and gender differences in the ASD population. Findings also support the need to consider biological sex in design and statistical analysis of intervention studies and trials that utilize the VABS and/or MSEL. Additionally, findings from analyses of matched samples have important implications for both researchers and clinicians who use the VABS and MSEL. Parent-report measures like the VABS are commonly used in research and clinical settings, particularly when assessment is required at multiple time points, because they are often easier to administer and less resource intensive than direct observation assessments. Parent-report measures also allow for remote data collection (e.g., phone interview; parent questionnaire), whereas standardized assessments that involve direct assessment are less likely to be suitable for remote administration, especially in young children. In the context of intervention research, the potential that parents are underreporting receptive language and fine motor skills may indicate the need for researchers to include outcome measures that utilize direct observation of skills in their study designs. Similar considerations may be advisable in clinical settings that require documentation of treatment progress. Additional research is needed to determine whether discrepancies between parent-report and direct observation are consistent in magnitude and direction over time.

It is also important to consider effect sizes observed for statistically significant comparisons in the current study, which ranged from small to moderate. This translates to mean differences in age equivalency scores ranging from 1 to 3 months depending on the comparison. In a sample of toddlers, these differences could be meaningful, particularly for researchers or clinicians attempting to document treatment-related change. When interpreting and potentially applying these findings in their own work, researchers, clinicians, and other stakeholders should consider whether a difference of this magnitude is meaningful for their purposes. For example, these findings are likely more relevant to researchers planning to measure change in receptive language as a dependent variable than for researchers planning to include receptive language as a covariate in statistical analyses.

Future Research and Limitations

While findings from the current study suggest that child SAB may moderate the relationship between parent report and direct assessment of certain areas of development, including expressive language, future research should explore if similar results also emerge in older children. Data examined in the current study were from children who were, on average, two years old at the time of evaluation, thereby limiting external validity to older children. Moreover, given recent research on linguistic camouflaging (Parish-Morris et al., 2017), it is important to better understand when masking behaviors emerge in children with ASD and how camouflaging behaviors may influence level of consistency between reporters of development for girls and boys with ASD. Specifically, future research should examine the developmental trajectory of adaptation and compensatory behaviors throughout the lifespan for both boys and girls with ASD, and how these behaviors at different ages may impact reporter consistency. Similarly, it would be interesting to assess if and how this dynamic may be impacted by severity of ASD symptoms.

In the current study, approximately 90% of the parent reporters in both the AMAB and AFAB groups were mothers. More research is needed to determine if the relationship between SAB and reporter consistency is different when fathers compared to mothers are the reporters. Likewise, future research should investigate the dynamic when parent report is compared to teacher report, or when comparing teacher report to direct testing.

Finally, since parent report measures of ASD symptoms were not utilized in the Get SET Early trial, analyses in the current study were limited to developmental domains measured by the VABS and MSEL. It is important for future research to assess the relationship between child SAB and reporter consistency for ASD symptoms. This could be accomplished by comparing data from the ADOS (Lord et al., 2012) and parent-report measures like the ADI-R (Rutter et al., 2003) or SRS-2 (Constantino & Gruber, 2012).

Conclusions

In summary, the current study is the first, to our knowledge, to examine if child SAB moderates the relationship between parent report and direct assessment of development in toddlers with developmental delays. Results indicate that parent-report measures and direct assessment may differ when measuring receptive language and fine motor skills, and that child SAB appears to influence parent-diagnostician consistency for expressive language. Given that parents are usually the first to notice signs of autism in their child, understanding how SAB might influence a parent’s impression of various aspects of development, and how these impressions may differ to pediatric health providers’ clinical impressions, could help improve early ASD screening, diagnosis, and intervention for both boys and girls.

Acknowledgements.

We would like to thank the families who participated in this research. Preliminary findings from this study were presented at the 2020 Annual Meeting of the International Society for Autism Research (INSAR). This study was funded by a grant from the National Institute of Mental Health (R01 MH104446 PI Karen Pierce) which supported the evaluation component of the study.

Footnotes

Disclosure of Conflict of Interest: The authors have no conflict(s) of interest to declare.

Data Availability Statement.

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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Associated Data

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

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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