Moritz von Zahn 

Date/Time: 20.02.2026, 10:30 

Location: D2.2.094 

Abstract 

Businesses increasingly rely on mobile notifications to increase app engagement, yet their effectiveness is typically evaluated based on immediate click-based responses. We examine whether the total effect of mobile notifications on app engagement extends beyond such immediate reactions. Drawing on theories of curiosity and memory, we distinguish between immediate, click-based effects and sustained effects that persist even after a notification is dismissed. To disentangle these mechanisms, we combine a preregistered large-scale field experiment with one million users of a major customer-loyalty app with an exogenous shock in the form of a global mobile operating system update that cleared notifications from users’ devices. We find that mobile notifications increase app engagement by 32.1 percent on average. However, clicks account for only a third of this total effect and occur almost exclusively in the immediate hours following the notification. The remaining two thirds reflect sustained, click-independent effects that extend into the following day. Exploiting the operating system update, we show that these sustained effects are at least partly driven by a memory effect, whereby the increase in app engagement persists even after the notification has been removed from the device. Finally, we examine how these distinct mechanisms inform notification policies for a heterogeneous consumer base. Using off-policy evaluation, we demonstrate that policies that account for sustained effects outperform approaches based solely on immediate click-based responses. Our findings contribute to research on consumer apps and provide guidance for firms seeking to evaluate and design effective mobile notifications.