A review and content analysis of engagement, functionality, aesthetics, information quality, and change techniques in the most popular commercial apps for weight management

Abstract

Background: There are thousands of apps promoting dietary improvement, increased physical activity (PA) and weight management. Despite a growing number of reviews in this area, popular apps have not been comprehensively analysed in terms of features related to engagement, functionality, aesthetics, information quality, and content, including the types of change techniques employed.

Methods: The databases containing information about all Health and Fitness apps on GP and iTunes (7,954 and 25,491 apps) were downloaded in April 2015. Database filters were applied to select the most popular apps available in both stores. Two researchers screened the descriptions selecting only weight management apps. Features, app quality and content were independently assessed using the Mobile App Rating Scale (MARS) and previously-defined categories of techniques relevant to behaviour change. Inter-coder reliabilities were calculated, and correlations between features explored.

Results: Of the 23 popular apps included in the review 16 were free (70%), 15 (65%) addressed weight control, diet and PA combined; 19 (83%) allowed behavioural tracking. On 5-point MARS scales, apps were of average quality (Md = 3.2, IQR = 1.4); "functionality" (Md = 4.0, IQR = 1.1) was the highest and "information quality" (Md = 2.0, IQR = 1.1) was the lowest domain. On average, 10 techniques were identified per app (range: 1-17) and of the 34 categories applied, goal setting and self-monitoring techniques were most frequently identified. App quality was positively correlated with number of techniques included (rho = .58, p < .01) and number of "technical" features (rho = .48, p < .05), which was also associated with the number of techniques included (rho = .61, p < .01). Apps that provided tracking used significantly more techniques than those that did not. Apps with automated tracking scored significantly higher in engagement, aesthetics, and overall MARS scores. Those that used change techniques previously associated with effectiveness (i.e., goal setting, self-monitoring and feedback) also had better "information quality".

Conclusions: Popular apps assessed have overall moderate quality and include behavioural tracking features and a range of change techniques associated with behaviour change. These apps may influence behaviour, although more attention to information quality and evidence-based content are warranted to improve their quality.

Keywords: Behaviour change techniques; Mobile apps; Mobile health (mhealth); Smartphone; Weight loss; Weight management.

Fig. 1

Flow chart of the selection process for apps included in the review. Legend: ^a Apps that were downloaded less than 10,000 times. In Google Play, the category ‘Installs’ includes the information 15 levels ranging from “1–5” to “10,000,000–50,000,000”. A popularity index, based on the category of installs, was determined to estimate the number of downloads, as described in Garg and Telang’s formula [53]. ^b Apps that were downloaded less than 100 times a day, based on the rank of the apps. ^c Apps that received a rating below 4. ^d Apps that were classified as having “in-app purchases” (i.e., " freemium"). ^e Apps that addressed other health aspects different from weight management or related behaviours (diet and PA), such as smoking, mental health, pregnancy, etc. ^f Apps that were workout or activity tracking apps without the aim to weight loss. ^g Apps whose description was not in English. ^h Apps that did not have a respective counterpart on the other app store. ⁱ Apps that had more than one version (e.g., HD, lite, pro); the basic, fully-functional version was chosen. ^j Apps that required an external device (e.g., monitor, wrist band) to function. ^k Apps that were either free or paid but the paid version did not have additional and fully functional features. ^l Apps that were not available to download after the selection or that were not available for download on the respective devices iPhone 5S (iOS 9.0.2) and Samsung Galaxy S4, GT-I9505 (Android 5.0.2)