The issue you're experiencing—where not all hook clicks are attributed as part of the experiment—likely stems from how and when the $experiment_started (Experiment Started) exposure event is being tracked.
Key points from Mixpanel documentation:
- The $experiment_started event should be sent only when a user is actually exposed to the experiment, i.e., when they see the specific test text, not just when they are assigned to a variant or open the site. This ensures that only users who truly experience the test are included in the experiment analysis.
- If the exposure event is not sent at the correct moment (e.g., it is sent too early, too late, or not at all for some users), subsequent events like hook clicks may not be attributed to the experiment. Mixpanel attributes user actions to a variant only after the exposure event is tracked for that user.
- The exposure event should be sent the first time a user is exposed to the experiment, and not for every session or page load. If a user is not exposed (does not see the test text), the exposure event should not be sent for them Experiments: Implementation for Experimentation.
Why are some hook clicks not part of the test?
- If a user clicks the hook button before the $experiment_started event is fired (i.e., before Mixpanel knows they are exposed to the experiment), those clicks will not be attributed to the experiment.
- If the exposure event is not reliably triggered for all users who see the test text, some users' actions will not be counted as part of the experiment.
How to resolve this:
1. Ensure the $experiment_started event is fired exactly when the user sees the test text—not before, not after. This should be the moment of exposure.
2. Verify that the event is sent for every user who sees the test text. Double-check your implementation to ensure there are no conditions or timing issues that could prevent the event from firing.
3. Do not send the exposure event for users who do not see the test text. This keeps your experiment sample accurate.
4. Check for race conditions: Make sure the $experiment_started event is sent before any possible hook click event can be triggered, so that Mixpanel can correctly attribute subsequent events to the experiment variant.
Example implementation:
```
// When the test text is rendered and visible to the user
mixpanel.track('$experiment_started', {
'Experiment name': 'Your Experiment Name',
'Variant name': 'Test'
});
// Now, any hook click will be attributed to the experiment
LBKS**Summary:**
