Table 2.

The most frequently used questionnaires for evaluating mHealth services

Questionnaire	Frequency (%)	Description of the questionnaire
System usability scale (SUS)	90 (36.5)	Brooke et al. designed the SUS questionnaire. This questionnaire was introduced for evaluating the usability of electronic systems. The SUS questionnaire has ten items that are not set in any specific categories. These items were designed with a 5-point Likert scale. SUS has a high level of reliability with a coefficient alpha of 0.91 [18, 19]
Mobile application rating scale (MARS)	88 (35.5)	Stoyanov et al. presented MARS for evaluating the quality of mobile health applications. This tool contains 23 items in six categories, including engagement, functionality, aesthetics, information quality, and subjective quality. MARS also has one separate section that is named app-specific. The items of MARS have a 5-point scale [12]. The construct validity of the MARS was confirmed with the confirmatory factor analysis (the root mean square error of approximation = 0.074, Tucker–Lewis index = 0.922, confirmatory fit index = 0.940, standardized root mean square residual = 0.059). The reliability of this tool was also confirmed by Omega 0.79–0.93. The Concurrent validity of MARS showed that it correlates with ENLIGHT (p < 0.05) [20]
Post study system usability questionnaire (PSSUQ)	15 (6)	Lewis [21] developed the PSSUQ to evaluate user satisfaction with the system usability at the end of his study. The last version of this questionnaire has 16 questions in three sections, including system usefulness, information quality, and interface quality. These questions were designed with a 7-point Likert scale. The criterion validity of the PSSUQ showed a moderate correlation (r = 0.80) with other measures of user satisfaction. The reliability of PSSUQ is confirmed with a coefficient alpha of 0.96 [21]
user mobile application rating scale (uMARS)	12 (5)	Stoyanov et al. introduced the uMARS as an end-user version of the MARS in 2016. uMARS has 20 items in five sections, including engagement, functionality, aesthetics, information quality, and subjective quality. The perceived impact is an additional section in uMARS. The items of uMARS have a 5-point scale. The internal consistency of uMARS has been confirmed by Cronbach alpha = 0.90. The reliability of uMARS has been shown by the Intraclass Correlation Coefficient = 0.70 [22]
Technology acceptance model (TAM)	11 (4.5)	Davis [23] designed a questionnaire based on the TAM. TAM displays how users use and accept technology. The TAM questionnaire has 12 items that are arranged in two sections, including the perceived usefulness and perceived ease of use. This questionnaire showed high discriminant, convergent, and factorial validity. The reliability of the TAM has been confirmed with a Cronbach alpha of 0.98 for usefulness and 0.94 for ease of use sections [23]
Computer system usability questionnaire (CSUQ)	6 (2.5)	Lewis [24] designed the CSUQ to evaluate user satisfaction with the system usability. This questionnaire is similar to PSSUQ with different wording. CSUQ contains 19 items with a 7-point Likert scale. The reliability of CSUQ has been confirmed by Coefficient alpha more than 0.89 [24]
Net promoter score (NPS)	5 (2)	Reichheld presented the NPS to measure customer satisfaction. The only item of this tool is the following question: “How likely is it that you would recommend to a friend or colleague?” NPS has an 11-point scale [25]
Health information technology usability evaluation scale (Health-ITUES)	5 (2)	Yen et al. [26] developed Health-ITUES based on the Health IT Usability Evaluation Model (Health-ITUEM). This questionnaire has 20 items in four sections, including quality of work-life, perceived usefulness, perceived ease of use, and user control. The items of Health-ITUES have a 5-point Likert scale. The reliability and validity of this questionnaire confirmed with Cronbach’s alphas ranged from 0.81 to 0.95, and factor correlations ranged from 0.37 to 0.66 [26]
The usefulness, satisfaction, and ease of use (USE)	4 (1.5)	Lund et al. presented the USE questionnaire for assessing the usability of a system’s user interface. This questionnaire has 30 items in four sections, including usefulness, ease of use, ease of learning, and satisfaction. These items have a 7-point Likert scale [27]. The high correlations between the USE dimensions and the SUS (r between 0.60 and 0.82, p < 0.001) showed the validity of this questionnaire. The reliability of USE has been confirmed with Cronbach’s alpha = 0.98 [28]
Client satisfaction questionnaire (CSQ)	4 (1.5)	Larsen et al. [29] introduced the CSQ for evaluating user satisfaction with different services. This questionnaire has eight items with a 4-point scale. The reliability of CSQ has been confirmed with the Coefficient alpha = 0.93 [29]
Unified theory of acceptance and use of technology (UTAUT)	4 (1.5)	Venkatesh et al. [30] developed the UTAUT questionnaire based on the UTAUT model to assess user acceptance of technology. UTAUT consists of 16 items in four sections, including performance expectancy, effort expectancy, social influence, and facilitating conditions. The items are scaled with a 7-point Likert scale [30]
Questionnaire for user interaction satisfaction (QUIS)	3 (1)	Chin et al. [31] presented the QUIS to evaluate the usability of the system and interaction with the computer interface. QUIS has 27 items in five sections, including the overall satisfaction, screen, terminology and information, learning, and system capabilities. The items were designed with a 10-point scale. The factor analysis of this questionnaire showed satisfactory validity. The reliability of the QUIS was confirmed with Cronbach's alpha = 0.94 [31]
User experience questionnaire (UEQ)	3 (1)	Laugwitz et al. [32] introduced the UEQ for evaluating usability and user satisfaction. UEQ has 26 items in six sections, including attractiveness, perspicuity, efficiency, dependability, stimulation, and novelty. The items of this questionnaire are scaled using a 7-point scale. The factor analysis of this questionnaire showed satisfactory validity. The reliability of the UEQ was confirmed with Cronbach's alpha more than 0.71 [32]
After-scenario questionnaire (ASQ)	3 (1)	Lewis [33] designed the ASQ for evaluating user satisfaction in scenario-based usability testing. This questionnaire has three items with a 7-point graphical scale. The factor analysis of this questionnaire showed satisfactory validity. The Concurrent validity of the ASQ showed that it correlates with the scenario completion data (p < 0.01) The reliability of the ASQ was confirmed with the Coefficient alpha more than 0.90 [33]
mHealth app usability questionnaire (MAUQ)	2 (0.5)	Zhou et al. [17] developed the MAUQ for assessing the usability of interactive and standalone mHealth applications. The MAUQ for interactive applications has 21 items in three sections, including ease of use and satisfaction, system information arrangement, and usefulness. However, the MAUQ for standalone applications has 18 items in three sections including ease of use, interface and satisfaction, and usefulness. All items have a 7-point scale. The factor analysis of this questionnaire showed acceptable validity. The criterion and construct validity of MAUQ showed that it correlates with the PSSUQ (r = 0.8448) and the SUS (r = 0.6425). The reliability of the MAUQ was confirmed with Cronbach's alpha more than 0.80 [17]
Game experience questionnaire (GEQ)	2 (0.5)	Poels et al. [34] presented the GEQ for evaluating the satisfaction of digital game users. This questionnaire has 42 items with a 5-point scale. The factor analysis of this questionnaire showed acceptable validity. The reliability of the GEQ was confirmed with Cronbach's alpha more than 0.70 [34]
The perceived ease of use and usefulness questionnaire	2 (0.5)	Davis [23] designed the Perceived Ease of Use and Usefulness Questionnaire. This questionnaire has 12 items that are arranged in two sections, including perceived usefulness and perceived ease of use. All items are scaled with a 7-point scale. This questionnaire showed high discriminant, convergent, and factorial validity. The reliability of The Perceived Ease of Use and Usefulness Questionnaire has been confirmed with a Cronbach alpha more than 0.94 [23]