What is Time to
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First Review
Speed of review Time to merge measures how responsive a team is in responding to and resolving pull requestsfast a Pull Request (PR) was merged after creating it.
Why
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Time to First Review matters
Speed of review affects a team's ability to deliver software. If review/approval is slow, the context is lost for the author.
What ‘good’ looks like
Inspection rates typically hover at 60 minutes per 500 lines of code (LOC). Whilst it can be tempting to focus on speed at the expense of a quality review, this defeats the purpose of the task at hand.
Similarly, watch out for Pull Requests Time to first Review affects your author’s ability to minimise context switching and supports the team to make frequent deployments into production.
PRs that are taking a long period of review time (several hours or more) relative to their size . This may indicate that your team’s review process may be blocking, and provides an opportunity to jump into the Pull Request to observe whether the number of reviewers on comments on the Pull request are slowing the process down.
How Umano measures this
Identify the time from when the author submits a pull request to when the first approval or first decline during each given intervalis blocking.
What ‘good’ Time to First Review looks like
A short time to merge indicates a culture of strong team responsiveness, collaboration and continuous delivery. PRs are opened and merged within a day reflect more mature practices. This is made possible by the author’s well constructed title (self-explanatory), description (
How Umano measures Time to First Review
For each of the PRs that are merged during a particular interval, Umano takes the time difference between when the PR was created and the time when it was merged.
Practices that influence this measure
Number of comments on a PR
Number of tasks on a PR
Size of the PR
Number of issues addressed in a PR
Reviewers are assigned in the PR
Number of times a PR has been reviewed
Time to first review
What’s included?
Each model looks and specific activities within the tools. Below a list of activities that contribute to Balance of Communication to Time to First Review and activities that do not have an impact on this metric.
Included | Not included |
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All Pull Requests in selected repositories. | If the review is done by the author him/her-self then it is not considered a review. Any additional review undertaken after the first review. |
Tips for improving Time to
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First Review
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Code reviews in reasonable quantity, at a slower pace for a limited amount of time results in the most effective code review |
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Shout out for Pull Requests that are deleting lines of code as this usually indicates a good clean-up of the code base, removal of technical debt and improves maintainability of the code base |
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Review fewer than 400 lines of code at a time for effective defect detection |
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Break down larger features into smaller Pull Requests |
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Submit Pull Requests on the day the code is ready for review, rather than waiting to submit all requests at the back of the sprint and causing a backlog for your peers to work through |
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Make the description useful by describing WHAT has changed, WHY this PR exists, HOW it is meant to work, and use screenshots where appropriate |
Resources
Dias, H., The anatomy of a perfect pull request, 2018, <https://medium.com/@hugooodias/the-anatomy-of-a-perfect-pull-request-567382bb6067 >
Osepchuk, B., Optimal pull request size, 2017, <https://smallbusinessprogramming.com/optimal-pull-request-size/>
Riosa, B. The (written) unwritten guide to pull requests, 2016, <https://www.atlassian.com/blog/git/written-unwritten-guide-pull-requests >
Dias, H., The anatomy of a perfect pull request, 2018, <https://opensource.com/article/18/6/anatomy-perfect-pull-request>
Hewa, G., How Big is Your Pull Request?, 2017, <https://hackernoon.com/how-big-is-your-pr-32c4d67ad76c>
Yu, Y., Wang, H., Filkov, V., Devanbu, P. and Vasilescu, B., 2015, May. Wait for it: Determinants of pull request evaluation latency on GitHub. In Mining software repositories (MSR), 2015 IEEE/ACM 12th working conference on (pp. 367-371). IEEE.