Table 4.
Ranking criteria with weighting factor (percentage of the overall score), item name, description and condition to be fulfilled, or their explanation.
| Variable | Source | Description | Score (%) |
| medicalDevice | Keyword-based evaluation of the store description (0: no keywords mentioned, 1: entry made) | The regulatory status (medical device) of the app is mentioned or explicitly excluded in the store description or there is mention of a seal of approval (reference to CEa, FDAb, medical device, or a seal of approval) | 20 |
| descriptionLength | Calculated value (number of characters) | Length of the store description | 20 |
| averageUserRating | Store metadata (from (0, maximum scoring reached) normalized to value range [0,1]) | Average rating of all versions of the app | 15 |
| userRatingCount | Store metadata (from (0, maximum number of ratings) normalized to value range [0,1]) | Overall number of user ratings that were obtained (for all versions) | 15 |
| sellerUrl | Evaluation of the metadata field sellerUrl for a valid URL (defined as nonempty and unequal to http:// or https:// without any further information); 0: invalid or empty, 1: valid URL | Link to a website (eg, a manufacturer’s homepage or a Web page for the app) has been provided | 10 |
| releaseNotesLength | Calculated value (between (0, maximum number of characters) normalized to [0,1]) | Length of the release notes, if available (prerequisite: at least one update, as only then must the field be set) | 10 |
| actuality | Calculated value including the time span between publication and readout time (from (0, maximum time span) normalized to 1-[0,1]) | Whether the app is up to date | 10 |
aCE: Conformité Européenne.
bFDA: Food and Drug Administration.