Pull request cycle time (or PR cycle time) is the total time a pull request spends in all stages of the development pipeline.
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In Swarmia, a pull requests cycle time is the sum of these three components:
Time in progress — from the first commit or from when the pull request is opened, whichever happens first, to the first review request.
Time in review — from the first review request (or from when the pull request was opened, if none) to the final approval.
Time to merge — from the final approval to once the pull request is merged.
A pull request is opened on a Monday and then the first review is requested on Wednesday, that equals 2 days 'in progress'.
Then that pull request takes another day for review approval, that equals 1 day in 'review'.
And finally, another full day passes between the final approval and the pull request being merged. That’s 1 day time to merge.
Together this equals a pull request cycle time of 4 days.
The average PR cycle time for a given time period would be the cycle time of all pull requests in that time period, averaged.
Lower cycle time means:
Shipping in small batches without interruptions
Getting feedback from end users faster
Reducing risk and overhead
Reviewing and merging new code quickly
According to the authors of Accelerate, “elite” teams reach a cycle time of less than a day, while high-performing teams deliver code in under 7 days on average.
Let's consider the key factors contributing to cycle time, and how you can impact them. Among others, we suggest focusing on the following:
Work in progress queue Working on too many pull requests at once often correlates with longer delivery times. Use Swarmia's WIP working agreement to agree on a target with the team (e.g. up to 10 pull requests open at once) and keep track of it over time.
Time in progress Shorter in progress time means focusing on splitting work into smaller batches that are easy to plan, review and deploy.
Time in review Creating smaller pull requests that are easy to review, using code owners in Github to assign reviewers automatically once a pull request is open are some ways to lower review time.
Pull request size Smaller pull requests are easier to plan, review and deploy.
Time to merge Making approved pull requests a priority, agreeing on merge rituals with the team (Who has the responsibility to drive the pull request forward? Who can merge code?), and investing in production infrastructure helps to reduce waiting time between approval and merge.
If measuring cycle time wasn't ever a priority, there are likely some very old pull requests waiting to be closed. Use Pull Request overview to identify old pull requests and decide what to do with them.
You can bulk exclude all pull requests that have been open for a month or longer, or archive individual ones. We recommend starting with the bulk exclusion, as you can include any excluded pull requests back into metrics later.
Once you've identified cycle time as an improvement area, look at the Pull Request insights together with the team:
Decide what a realistic maximum target is (7 to 14 days is a good starting point).
Use to look into cycle time and other pull request metrics in Swarmia.
To get a more relevant view of your data, outlier pull requests from all metrics. This lets you focus on lowering cycle time for newly opened pull requests.
Adopt a and set it to what you just decided.
To address specific issues contributing to cycle time, consider adopting a , and an agreement measuring specifically
Enable in Slack to get a daily reminder about pull requests not adhering to the agreement. Check regularly with the team to spot emerging coding patterns early and close pull requests before they get old and stale.
