A common problem when running experiments is conflating the assignment of a user to a variant with the exposure of a user to the same variant. In other words, just because a user has been assigned a variant for a flag, doesn't always mean they have been exposed to the variant within an application.
For example, if we have setup an experiment for a new check out UI where the exposure event is incorrectly kept as the default Assignment, then users who are assigned a variant (e.g. treatment) but never exposed to the checkout page may skew the experiment results.
Client-side Experiment SDKs now provide a mechanism to automatically generate exposure events, which are tracked via a configured analytics provider interface. The exposure event is generated and tracked when the variant() method is called and a valid variant is found in the SDKs storage.Automatic Exposure Tracking with Amplitude Analytics SDK integration is now available on all client-side Experiment SDKs (JavaScript, iOS, Android, and React Native).
