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Optimizely Knowledge Base

Optimizely Classic Mobile apps: Measure retention

  • Track the percentage of unique visitors who return to the app after they enter an experiment
  • Measure the impact of your variations on visitors' behavior in your app

Retention is one of the most important metrics in mobile applications. In Optimizely, retention tracks the percentage of users who return to your app after they've been bucketed into an experiment. Use this metric to measure the impact of your experiment variations on users' engagement with your app.

In Optimizely, the retention metric is tracked automatically and will appear on your Results page if you have Optimizely's Mobile SDK version 1.4+. To update your Optimizely SDK, check out these guides on Android and iOS.

Optimizely uses mobile sessions to track user retention. Click to learn more about mobile sessions.

Get started

To start optimizing for user retention, visit our guides on getting started for Android and iOS.

Once your app is live in the App Store or Play Store with the Optimizely SDK, you can create and run your first Optimizely mobile experiment.

View retention on the Results Page

The Retention Summary and Charts will automatically appear on the Results page for every experiment you run, once you have Optimizely's Mobile SDK version 1.5+.


The retention summary shows the percentage of users who return to the app after first seeing the experiment. The summary breaks down the period during which visitors first return, from 1 day, 2-3 days, 4-7 days, and 8-14 days.

X axis: Number of days after which a visitor returned to the app after entering the experiment.

Y axis: Percent of visitors who returned to trigger the retention goal in a given time period.

Use this overview to compare how the original experience and variations impact user retention in your app over time.

Use segments to get a more granular view of retention in your new users. To learn how to segment by new versus returning users, check out this article on Mobile Attributes.


On the Results page, you'll also find charts that segment retention by the period when the users return, across the life of your experiment.

Below is a sample of the chart for users who return after 1 day. Note that this view shows you 1-day retention for users who entered the experiment between April 11, 2016 and May 11, 2016.

Use this view to track how your experiment variations impact your users' retention rate within a certain timeframe: 1 day, 2-3 days, 4-7 days, and 8-14 days.