Kevin Xu:

There are plenty of metrics you can track—stars, forks, pull requests (PRs), merge requests (MRs), contributor counts, etc.—but more data doesn’t necessarily mean clearer insights. I’ve previously shared my skepticism about the value of these surface-level metrics, especially when assessing an open source project’s health and sustainability.

In this article, I propose two second-order metrics to track, measure, and continually optimize to build a strong, self-sustaining open source community

Those two metrics? Breakdowns of code reviewers and leaderboards of different community interactions. (He also explains why. Worth a read.)