No‑Review PR Dev Day Ratio (NRR)
No‑Review PR Dev Day Ratio (NRR) tracks how much developer effort is spent on pull requests that are merged without any code review. It highlights cases where review processes are bypassed—intentionally or accidentally—and helps assess the reliability of code validation practices.
Calculation
NRR is typically reported weekly or per sprint using minware’s dev day attribution model.
The metric is calculated as:
NRR = development days on unreviewed merged PRs ÷ total dev days × 100
Goals
NRR helps teams identify lapses in code review discipline. It answers questions like:
- Are PRs being merged without peer validation?
- Is review culture being applied consistently?
- Are fast-track or emergency merges undermining quality standards?
High NRR often correlates with anti‑patterns like Bypassing Pull Requests, and may precede integration issues or quality regressions.
Variations
NRR may also be referred to as Unreviewed Merge Ratio or Review Omission Rate. Common segmentations include:
- By team or repo, to highlight areas where review standards vary
- By engineer, to surface gaps in onboarding or workflow understanding
- By commit urgency, such as hotfixes vs. planned features
Tracking these variations helps teams identify whether no‑review merges are legitimate (e.g., urgent patches) or indicate process breakdown.
Limitations
NRR measures absence of review but not merge quality or risk. An unreviewed trivial change may pose less risk than a large feature that goes unchecked. It also assumes accurate attribution of dev days for unreviewed PRs.
To understand the impact, pair NRR with:
| Complementary Metric | Why It’s Relevant |
|---|---|
| Merge Success Rate | Indicates whether unreviewed PRs merge cleanly or fail integration checks |
| Review Latency | Shows if review bypass is driven by slow feedback loops |
| Direct Main Commit Dev Day Ratio (DMR) | May correlate with patterns of bypassing established PR workflows |
Optimization
Improving NRR encourages consistent review discipline and safer delivery pipelines:
- Enforce branch protection rules that require at least one approval before merge
- Set clear Code Review Standards, so developers know when a review is mandatory
- Monitor unreviewed merges via dashboards and address lapses early
- Speed up reviews for critical changes, balancing velocity and safety
- Train teams on review value, emphasizing review benefits rather than gatekeeping
NRR is a proxy for review culture integrity. A low NRR indicates mature, accountable practices. A rising NRR warns of potential quality and integration risks.
