Signal definition
Commit Velocity
A raw measure of engineering output. Useful as a baseline; not directly predictive on its own. The signal investors should watch is the rate-of-change (commit velocity change), not the absolute number.
Unit: commits per 14-day window · Window: 14 days, rolling
Formula
count(commits to default branch where committed_at within [t − 14d, t])Decision rule
Signal fires when commit velocity in the current window exceeds the prior window by ≥40% AND absolute count ≥10 commits.
Common pitfall
Repos using squash-merging report dramatically lower commit counts than rebase/merge-commit repos for the same amount of work. We normalize by repo merge style; raw GitHub counts do not.
Empirical findings about commit velocity
Median 14-day commit velocity for VC-backed startups: 71 commits
The 14-day commit-velocity median across 55 venture-backed startups is 71 commits.
Mean commit velocity is 173, over 2.4× the median
Mean commit velocity is 173, over 2.4× the median, indicating a heavy upper tail.
Top decile commit velocity: 392 commits per 14 days
The 90th percentile commit velocity is 392 commits per 14 days.
Related signals
Defined in the SSRN-indexed methodology paper. Full definition, assumptions, and validation in §3 of the paper. Reproducibility kit at /reproducibility. Glossary entry at /glossary#commit-velocity.
Five breakout startups, every Sunday, before the round gets crowded
The free Acceleration Watch: five venture-backed teams accelerating on the engineering signal, translated into plain English, 21 to 47 days before the deck circulates. No code-reading, no card.