Objective: Young children use mobile devices on average 1 hour/day, but no studies have examined the prevalence of advertising in children's apps. The objective of this study was to describe the advertising content of popular children's apps.
Methods: To create a coding scheme, we downloaded and played 39 apps played by children aged 12 months to 5 years in a pilot study of a mobile sensing app; 2 researchers played each app, took detailed notes on the design of advertisements, and iteratively refined the codebook (interrater reliability 0.96). Codes were then applied to the 96 most downloaded free and paid apps in the 5 And Under category on the Google Play app store.
Results: Of the 135 apps reviewed, 129 (95%) contained at least 1 type of advertising. These included use of commercial characters (42%); full-app teasers (46%); advertising videos interrupting play (e.g., pop-ups [35%] or to unlock play items [16%]); in-app purchases (30%); prompts to rate the app (28%) or share on social media (14%); distracting ads such as banners across the screen (17%) or hidden ads with misleading symbols such as "$" or camouflaged as gameplay items (7%). Advertising was significantly more prevalent in free apps (100% vs 88% of paid apps), but occurred at similar rates in apps labeled as "educational" versus other categories.
Conclusion: In this exploratory study, we found high rates of mobile advertising through manipulative and disruptive methods. These results have implications for advertising regulation, parent media choices, and apps' educational value.