The percentage of files changed receiving at least one code review comment
Calculation: A count of the number of files with at least one comment in the review divided by the number of files changed in the pull request, expressed as a percentage.
Why it matters: A healthy code review process is thorough, yet efficient. Review Coverage is a proxy for review thoroughness. You want to make sure that reviewers aren’t rubber-stamping changes and aren’t being overly nit-picky and slowing down the whole process.
How to use it: Consider Review Coverage in conjunction with Review Influence, which will give you an understanding of how the quantity of feedback compares to its actionability.
High Review Coverage and low Review Influence for a team can indicate that reviewers are providing feedback that isn’t being perceived as valuable to the submitter. This may call for a re-alignment around how code reviews should be conducted.
If an individual has significantly higher Review Influence than typical for your team, look at their reviews and see if they could be used as a model for the rest of the team. If Review Influence is low for a particular reviewer, it may present a coaching opportunity.
Review coverage considers initial code reviews only (not subsequent reviews).