Table 2

App privacy-related and security-related evaluation methods and results

Privacy policySocial mediaPermissions requestedData security
MethodsResultsMethodsResultsMethodsResultsMethodsResults
Bry et al 43 Evaluated app store page and/or downloaded app manually Privacy policy presence: Less than 5% of appsEvaluated app store page and/or downloaded app manually Login and/or password presence: Less than 5% of apps
Cheng et al 24 Evaluated app store page and/or downloaded app manually Investigator-developed security assessment scale: 6% of apps rated as excellent; 10% of apps rated as good
Das et al 20 Statistics calculated with web-based readability calculator Privacy policy readability: average reading grade level (12.8) higher than average US adult level (8.0)
Liu et al 22 Comparison of app library package names with libraries relevant to social networks Potential for social medial sharing: 20% of appsExamination of privacy grade as listed in online crowdsourced dataset Potential for permission requests: 82% of apps use few permissions for unusual purposes; 10% may use permissions in this way
Meyer et al 23 Evaluated app store page and/or downloaded app manually Social media links: 14% of appsEvaluated app store page and/or downloaded app manually Permission requests:
100% of apps Requests for notifications (100%), files/photo storage (53%), phone (13%), microphone (8%), camera (7%); and location (4%).
Musgrave et al 50 Evaluated app store page and/or downloaded app manually Login and/or password presence: 90% of apps required logins; 70% required passwords
Reyes et al 18 Automated analysis of whether data transmissions are protected Data encryption: 40% of apps do not use TLS*
Robinson et al 53 Evaluated app store page and/or downloaded app manually Social media links: 63% of appsEvaluated app store page and/or downloaded app manually Login and/or password presence: 0% of apps
Sardi et al 21 Evaluated app store page and/or downloaded app manually Privacy policy presence: 63% of apps
Privacy policy content:
27% of privacy policies complied with international and federal laws including COPPA†, GDPR‡ and HIPAA§.
Evaluated app store page and/or downloaded app manually Social media links:
31% of apps
Evaluated app store page and/or downloaded app manually Login and/or password presence: 29% of apps
Cloud storage backup option: 8% of apps
Schoeppe et al 54 Evaluated app store page and/or downloaded app manually Social media links:
60% of apps
Evaluated app store page and/or downloaded app manually Login and/or password presence: 20% of apps
Schoffman et al 55 Evaluated app store page and/or downloaded app manually Social media links:
16% of apps
Virani et al 58 Evaluated app store page and/or downloaded app manually Privacy policy presence: 100% of appsEvaluated app store page and/or downloaded app manually Login and/or password presence: 33%–100% of apps
Weber et al 59 Evaluated app store page and/or downloaded app manually Social media links:
Less than or equal to 35% of apps
Evaluated app store page and/or downloaded app manually Login and/or password presence: 70% of apps
Zarnowiecki et al 63 Evaluated app store page and/or downloaded app manually Social media links:
25% of apps
Evaluated app store page and/or downloaded app manually Login and/or password presence: 0% of apps
  • *Transport Layer Security.

  • †Children’s Online Privacy Protection Act.

  • ‡General Data Protection Regulation.

  • §Health Insurance Portability and Accountability Act.