Experiment enrollment

When is a user enrolled?

Question

When a user receives a recipe, are they enrolled immediately or at the next session?

Answer

For first run experiments, the recipe is bundled with the app.

For existing users, the flow is:

1) Firefox starts

2) Existing enrollments are applied fast

3) Browser continues to start

4) Nimbus syncs and computes new enrollments

5) New enrollment prefs are set

So if your feature only reads prefs right at startup, then the pref wouldn't be applied until the following session.

tip

You can use isEarlyStartup to persist the prefs to disk so that they are available as soon as possible at startup.

Unenrollment

Question

If a client is unenrolled from an experiment (say they opt out of that experiment specifically) will they be able to enroll again if they meet the criteria?

Answer

No. Once a user is disqualified by opting out (or through targeting, etc.) the client keeps a record of that and won't enroll back into the same experiment.