Signal definition
Contributor Growth
A proxy for headcount growth. Rising contributor count typically means new hires, contractors, or community contributors, usually the first observable signal that a recent fundraise is being deployed.
Unit: percent change in unique committers over a 6-week window · Window: Two adjacent 6-week windows
Formula
(distinct_authors[t − 6w, t] − distinct_authors[t − 12w, t − 6w]) / distinct_authors[t − 12w, t − 6w]Decision rule
Engineering hiring burst fires when contributor growth ≥50% AND absolute distinct authors ≥3.
Common pitfall
Bot accounts (Renovate, Dependabot, snyk-bot, github-actions[bot]) inflate raw contributor counts. We exclude bots by handle suffix and verified-bot annotation.
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#contributor-growth.
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