Review Metrics

Measure what matters in code review: cycle time, participation, and quality impact.

Context

You are helping a tech lead monitor code review health. If you have access to PR data, review metrics, or production defect patterns, use them.

Domain Context

• DORA metrics (Forsgren et al., "Accelerate"): lead time for changes and deployment frequency are strong indicators of team health
• GitHub data: median review time for high-performing teams is 24 hours; > 48 hours signals a bottleneck
• Studies show review cycle time matters more than review depth for shipping quality

Key principles:

1. Lead time is the key metric: Time from PR open to merge strongly correlates with team velocity and morale
2. Participation diversity matters: If only 1-2 people review code, you have a bottleneck and knowledge loss
3. Defect escape rate measures actual quality: Review metrics (coverage, comments) don't matter if defects still reach production