Time to Approve Metric

Definition

The Time to Approve Metric measures the amount of time it takes for a pull request (PR) to receive final approval after it has been picked up for review. This metric is a key indicator of the efficiency and responsiveness of the code review process.

Why Is This Metric Useful?

Process Efficiency: Shorter approval times typically indicate streamlined review workflows and effective team collaboration.
Quality Assurance: Longer approval times can highlight potential issues, such as unclear PRs, inadequate documentation, or overburdened reviewers.
Team Productivity: Tracking this metric helps identify bottlenecks in the review process, enabling teams to implement strategies to improve overall productivity.

Factors Influencing Time to Approve

Clarity of the PR: Well-documented and concise PRs are reviewed faster.
Complexity of Changes: The PR contains intricate logic, algorithms, or domain-specific changes that require careful evaluation.
Large PR: Reviewing a large number of files or extensive changes takes more time to ensure nothing is missed.
Requested Changes: The reviewer identifies issues or areas for improvement, and the author needs time to address them.
Multiple Review Iterations: The back-and-forth between the author and reviewer prolongs the review process.
Insufficient Tests: The reviewer identifies missing test cases.
Interruptions: The reviewer may get interrupted by other high-priority tasks or meetings after starting the review.
Skill Gap: The reviewer may need extra time to understand parts of the code due to unfamiliarity with the domain or technology.
Reviewer Availability: Approval time may increase if reviewers are unavailable or over-allocated.

Monitoring the Time to Approve metric can help engineering teams refine their review practices, reduce delays, and ensure timely delivery of high-quality code.

Calculation

The Time to Approve metric is the duration between the moment a pull request (PR) is "picked up" (when the reviewer leave the first comment) and the moment it receives final approval.

PR Reviewed and Then Approved:

Time to Approve = Time of First Approval - Time the PR was Picked Up for Review

PR Approved Without Comments or Reviews:

Time to Approve = 0

Definitions:

Time of PR Approval: The timestamp when the pull request is officially approved by the reviewer(s).
Time of First Reviewer Comment: The timestamp of the first comment made by a reviewer (ignoring comments made by the PR author).