The German Version of the Mobile App Rating Scale (MARS-G): Development and Validation Study

Area of Science:

• Digital Health
• Health Informatics
• Software Quality Assessment

Background:

• The proliferation of mobile health apps (MHAs) necessitates robust quality evaluation methods.
• Existing app store ratings often lack accuracy, creating a need for standardized assessment tools.
• The Mobile App Rating Scale (MARS) provides a systematic approach to evaluating MHAs, but a German version was unavailable.

Purpose of the Study:

• To translate and validate the German version of the Mobile App Rating Scale (MARS-G).
• To ensure the MARS-G is a reliable and valid instrument for assessing German MHAs.

Main Methods:

• The original MARS underwent forward and backward translation to create the MARS-G.
• 104 MHAs were independently rated twice by eight bilingual researchers using both MARS and MARS-G.
• Statistical analyses, including internal consistency, validity, reliability, and Mokken scale analysis, were performed.

Main Results:

• The MARS-G demonstrated excellent alignment and comparable properties to the original MARS.
• High internal consistency (omega 0.72–0.91) and strong correlations (r 0.93–0.98) between MARS-G and MARS dimensions were observed.
• Good scalability was confirmed for both MARS (H=0.50) and MARS-G (H=0.48).

Conclusions:

• The MARS-G is a validated and reliable tool for assessing the quality of health apps in German-speaking populations.
• The overall score from the MARS-G serves as a dependable indicator of app quality.
• Further research is recommended to explore the factorial structure of both MARS and MARS-G.