This document summarizes the results of a test pilot program run by Mozilla to test new features in the Firefox browser. It found that only 7% of users accounted for 80% of the engagement, challenging the typical 80-20 rule. It publishes anonymous and aggregated user data as open resources for others to use. It also explains how it deals with self-selection bias in test pilot programs to improve the user interface of Firefox based on these results.

1. Test Pilot

3. Why/How We Built It

8. Data is available and understandable to
users, BEFORE they submit it.
Data in charts All raw data

9. Data is published as public resources
- Anonymous and aggregated user data samples
- Explanation on how to use the data

10. Surprises

12. 80%-20% rule?
More like 80%-7%

14. 20% used only one:

20. 92% kept tabs on top
70% kept new menu
New tab: 12% -> 88%

21. Resulting Changes in
Firefox UI

26. Dealing with Self-
Selection Bias

34. testpilot.mozillalabs.com
blog.mozilla.com/metrics
heatmap.mozillalabs.com
@MozTestPilot