7.3.3. Mobile apps

This intervention entails the implementation of a nation-wide introduction of a smartphone application promoting behaviours leading to weight reduction. These applications can help individuals count the numbers of steps they walk in a day, or estimate calories consumed by providing nutritional information for various foods and beverages. Further, they can take advantage of various technological options, for example by linking calorie information to product barcodes that can be scanned by phones; by generating charts on trends in calorie consumption and physical activity levels; by providing information on the nearby health and wellness events/facilities; by promoting health behaviours through various rewards programmes. It is assumed that the development and release of the application will rely on governmental marketing and promotion.

Based on an existing meta-analysis [Flores Mateo, Granado-Font, Ferr{\'{e}}-Grau and Monta{\~{n}}a-Carreras, 2015 [69]], the intervention is assumed to lead to a drop in BMI by 0.43 kg/m2 in participating people. In several studies included in the meta-analysis, mobile apps are compared with some control intervention (e.g. counselling or printed materials) rather than with a complete absence of any intervention, so this effect is likely to be an underestimate of the true effect. It is also assumed that those participating remain active for one year, and that the maximum effect (0.43 kg/m2 drop) is linearly achieved within one year. After that, people gradually revert to the old BMI within another year, as they decide not to use the app any longer.

The target group for this policy action is made up of individuals aged 15 to 64, broadly in line with the population groups included in the studies underlying the meta-analysis used to model the effectiveness of the intervention [Flores Mateo, Granado-Font, Ferr{\'{e}}-Grau and Monta{\~{n}}a-Carreras, 2015 [69]]. In addition, based on findings from a previous study [Goryakin et al., 2017 [22]], the population coverage is assumed to be 2.21% of the target group.

Intervention costs include the expenses of developing and updating the application, marketing it nationwide, as well as storing and processing the data generated by the application use. This cost varies between USD PPP 0.56 and USD PPP 0.63 annually per capita across the countries included in the analysis.