The Effect of Choice Screens on Mobile Browser Usage: Evidence from the EU Digital Markets Act

Can active choice mitigate the effects of preset defaults? We study this question using a difference-in-differences design around the rollout of the EU’s Digital Markets Act, which required iOS and Android to display browser choice screens under certain conditions. We find large effects, with notable differences across platforms: from 15 months after the mandate onward, Firefox usage was 113 percent higher on iOS and 12 percent higher on Android relative to a no-mandate counterfactual. This gap is consistent with rollout differences, as Android showed choice screens primarily on new devices, whereas iOS also showed them on existing devices.