Pull Request Analytics: How to Visualize Cycle Time / Lead Time and Get Insights for Improvement
Cycle Time / Lead Time is one of the most important metrics for software development. It can tell a lot about the efficiency of the development process and the teams’ speed and capacity. In the previous article, we showed you how to get a detailed report with the pull request statistics and Cycle Time / Lead Time calculated on the repository level.
Today we’ll tell you how to use this report:
- How to visualize the pull request data.
- What things to pay attention to.
- What insights you can get to improve performance.
Analyzing your codebase
First, you need to understand the current state of affairs and how it compares to the industry standards. According to the Code Climate’s research, the industry-wide median for Cycle Time is 3.4 days, with only the top 25% managing to keep it as low as 1.8 days and the bottom 25% having a Cycle Time of 6.2 days.
To get a better understanding of the development process, it might be helpful to look at the teams’ dynamics and monitor the changes over time. The following chart shows how the average Cycle Time changes month after month with a trend line, so you can see objectively whether the development process is getting faster or slower and check how your rates compare to the industry average. Follow the instructions to build this chart.
For a more precise analysis and evaluation of the current code base, you can also use the Cycle Time distribution chart that provides pull request statistics aggregated by their Cycle time value, making it easy to spot the outliers for further investigation. Learn how to build this chart.
In addition to the Cycle Time, Awesome Graphs for Bitbucket lets you analyze the pull request resolution time out-of-the-box. Using the Resolution Time Distribution report, you can see how long it takes pull requests to merge or decline, find the shortest and longest pull requests, and predict the resolution time of future pull requests with the historical data.
While Cycle Time serves as a great indicator of success and, keeping it low, you can increase the output and efficiency of your teams, it’s not diagnostic by itself and can’t really tell what you are doing right or wrong. To understand why it is high or low, you’ll need to dig deeper into the metrics it consists of. The chart below gives you a general overview of the pull requests on the repository level and shows the Cycle Time with the percentage of the stages it’s comprised of (which we’ll discuss in detail in the following paragraphs). You can build a chart like this using the Chart from Table macro, available in the Table Filter and Charts app.
Breaking down the Cycle Time
We break down Cycle Time into four stages:
- Time to open (from the first commit to open)
- Time waiting for review (from open to the first comment)
- Time to approve (from the first comment to approved)
- Time to merge (from approved to merge)
Now we’ll go through each of these stages, discussing the things to pay attention to.
Time to Open
This metric is arguably the most important of all, as it influences all the later stages and, according to the research, pull requests that open faster tend to merge faster.
Long Time to Open might indicate that the developer had to switch tasks and/or that code was rewritten, which might also result in large batch sizes. In one of the previous articles, we described how you can check the size of your pull requests in Bitbucket, so you can also use it for a deeper analysis.
One of the things you can do to improve your Time to Open is to decrease the pull request size to be no more than 200 to 400 lines of code. Thus you’ll influence each stage of the cycle, as the smaller pull requests are more likely to be reviewed more thoroughly and be approved sooner.
Time to Review
Time to Review is a great metric to understand if your teams adopted Code Review as part of the daily routine. If it’s high, then it might not be part of their habit, and you’ll need to foster this culture. Another reason might be that the pull requests are not review-friendly and the reviewers procrastinate dealing with them. You can change this, once again, by keeping the pull request size small and by writing a reasonable description so it’s easier to get started with them. If the long Time to Review rate is caused by organizational issues, then it might require reprioritization.
Time to Approve
This is the stage you don’t really want to minimize but rather make it consistent by reducing inefficiencies in the code review process. While there are many strategies for Code Review, there is hardly any industry standard for Code Review metrics, so you’ll need to focus on the organization of the process and try to find a way to get constructive feedback.
Time to Merge
Long Time to Merge might be an indicator that there are obstacles in the delivery workflow. To improve it, you need to find out if there are any blockers in the process, including manual deployment, and check if your tooling satisfies your current needs.
Cycle Time’s importance is difficult to overestimate, as this metric can tell a lot about the way you work, and controlling it, you can optimize the development process and deliver faster.
Once again, we built the initial pull request report with the help of the Awesome Graphs for Bitbucket app as a data provider and used the Table Filter and Charts for Confluence app to aggregate and visualize the data.
These are just a few examples, but you can get much more even from this one report. Check out the other guides for charts based on data from Bitbucket. Share your feedback and ideas in the comments, and we’ll try to cover them in future posts.