Micro-randomized trial · 2018
To Prompt or Not to Prompt? A Microrandomized Trial of Time-Varying Push Notifications to Increase Proximal Engagement With a Mobile Health App
Bidargaddi N, Almirall D, Murphy S, Nahum-Shani I, Kovalcik M, Pituch T, Maaieh H, Strecher V
What it found
At six possible times a day, users were randomly sent or not sent a tailored message. A message made people about 4% more likely to use the app in the next 24 hours. The time mattered: the effect was largest around 12:30 on weekends, at about 12%.
Where the evidence stops
The outcome is opening the app, not a change in behaviour or well-being. One commercial app, one population.
How it shapes Pursue
Pursue
Evidence that timing changes the effect of the same message, and that the effect on engagement alone is small.
A design input, not evidence that Pursue works.
Cited in
- 01When is the right moment for a reminder or a nudge?When the person is able to take it in, which changes from moment to moment. In a trial with 1,255 users of a workplace well-being app (Bidargaddi et al., 2018), the same message made people about 4% more likely to use the app in the next day, and about 12% more likely at 12:30 on weekends.Timing and receptivity
- 02Do reminder apps change what people do, or just how often they open the app?Often only the second. In a six-month University of Michigan trial with 287 adults with high blood pressure (Golbus et al., 2026), notifications made people use the app more but did not raise steps in the next hour or improve food choices the next day. Opening an app is engagement, not benefit.Engagement is not benefit