Table 2.

Questions regarding the relevance for each of the nine quality principles (translated from the original German version).

Principle	Perceived relevance
Practicality	How important is it to you that apps can be used for the intended purpose?
Risk adequacy	How important is it to you that apps are low risk in terms of health, social, or economic risks?
Ethical soundness	How important is it to you to avoid discrimination and stigmatization when developing, offering, operating, and using apps?
Legal conformity	How important is it to you that data protection, professional, and health regulations are respected in apps?
Content validity	How important is the validity and trustworthiness of the health-related content presented and used in an app to you?
Technical adequacy	How important are easy maintainability and platform-independent or cross-platform usability of apps to you?
Usability	How important is the target group–oriented design and operation of apps to you?
Resource efficiency	How important to you is the efficient use of resources through apps, for example in terms of battery and computing power?
Transparency	How important is it to you that apps provide transparent information about inherent quality features?