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Experiment Overrides

Learn how to override group allocation for experiments during development and testing.

Experiment overrides force chosen users into a specific experiment group instead of the group that randomization would assign. When your app fetches an experiment's parameters, Statsig checks overrides first and returns the overridden group immediately for any user who matches one. Use an override during development to put yourself into each group and confirm that every variant works. To test each variant across a whole environment without pinning individual users, enable the experiment for a lower environment instead.

You can override individual IDs, or add overrides based on feature gates and segments to force every user who passes a given gate or segment into a given group.

Overrides modal listing ID and conditional overrides for an experiment

How Statsig evaluates overrides

  • Statsig evaluates ID overrides first, then conditional overrides from top to bottom.
  • The ID type of an ID override doesn't have to match the experiment's ID type.
  • For experiments in a layer, set overrides at the layer level. Layers make their experiments mutually exclusive, so Statsig can override a user into only one experiment within a layer.
  • Add overrides before the experiment starts, or at least before a user's first exposure. Statsig excludes users whose first exposure came from an override from Pulse results, because those users aren't randomized. Adding a large number of users to an override can reduce the reliability of your results.

If you add an override after Statsig has already exposed a user to the experiment, Statsig honors the override but doesn't exclude that user from Pulse results. Statsig keeps attributing the user's events and metrics to the group it first assigned them to, even though the user now sees a different group. This can pollute your results. The impact depends on how many users fall into this category.

Add an override

  1. Log into the Statsig console and select Experiments in the left-hand navigation panel.
  2. Select the experiment where you want to add an override, then open the Setup tab.
  3. Click Manage Overrides, configure the override, and click Save.

Manage Overrides entry point on the experiment Setup tab

Delete an override

Remove an override you no longer need so that Statsig evaluates the experiment's rules as normal.

  1. Log into the Statsig console and select Experiments in the left-hand navigation panel.
  2. Select the experiment or layer that contains the override.
  3. Click Manage Overrides.
  4. Click the trash can icon next to the override you want to delete, then click Save.

Test an override

After you add an override, open the Diagnostics tab and use the Check Group for a User window. Enter the properties a user needs to pass the gate or segment that the override targets, and confirm which group Statsig returns.

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