When it comes to software development, no code is written in stone. Sooner or later, you need to change it to include new requirements or enhance some newly discovered quality issues. While these changes are fruitful to some extent, an excess of anything is bad. Tracking, measuring, and assessing these code changes can help you optimize your code quality and improve team performance while forecasting future risks at the same time. This is what code churn refers to. In this prose, we will discuss what code churn is, how to measure it, and how to prevent it by implementing different strategies. Let’s dig deep into:
What is Code Churn?
Code churn in software development indicates the frequency and extent of changes made in source code, for example, a file, a class, and a function. It measures how often developers insert new lines of code, delete outdated code, and change the existing code in the codebase of an application.
Take, for instance, if you have written 100 lines of code in the last couple of weeks and you modified or erased 30 of them, you have a code churn rate of 30%.
There can be more than one reason for this, including but not limited to:
- Bug Fixes: To find and resolve bugs in the code.
- Refactoring: To alter the code to make it cleaner and easier to maintain.
- New Features: To introduce new features or functionalities in the software.
- Scope Creep: To optimize the code to make it run quicker or enhance performance
It is a great practice to analyze and understand code churn patterns, as it comes in handy for development teams to:
- Maintain code quality
- Make informed decisions
- Improve their processes
In fact, as per Simpleprogrammer.com, industry experts think that code churn around 15% to 25% is fair enough for most teams, while below 15% indicates normal to highly efficient teams.
Example of Code Churn
An example of code churn can be seen in a mobile app development project where one feature is modified frequently. Assume that a team is building an eCommerce application and offers a new feature for discount calculation. However, as development progresses, the team realizes that it needs to modify the initial feature implementation to handle edge cases and improve performance. As a result, developers change, add, and delete several lines of code.
This example shows how code churn takes place owing to the need for continuous enhancement and optimization during the development process. In case you are not aware of edge cases, we must tell you that it is a problem or circumstance that takes place only at extreme operating parameters. For instance, when playing songs at full volume, a stereo speaker might produce distorted audio, even in the absence of any extreme setting or situation. Also, an edge case can be an expected or unexpected problem or situation.
5 Main Causes of Code Churn With Solutions
#1 Prototyping
Just to let you know, a high churn rate is common when a developer is discovering a new functionality as they explore and test multiple solutions to a problem. Teams generally use prototyping during the initial stages of a project, especially when the project is new or complex. In fact, teams often consider a very low code churn rate in the early stages of a project an indicator that the project is not progressing as planned.
When developers work on exploratory projects, they often relax code standards to create a proof of concept more quickly. They do this with the intention of improving the code after identifying the right solution. Although this approach produces a high code churn rate in the short term, it remains productive because developers can validate new ideas sooner rather than later. Some examples of cases where you may come across a large number of rewritten codes are:
- Redesigns
- Prototypes
- POCs
Solution
“So, next time you see a developer prototyping, don’t disturb them at all,” says the experts of the top digital transformation company. If a developer has a meeting scheduled that is not essential, consider extending the deadlines or letting them know that you are aware of their involvement in the project and that they do not need to attend unless they choose to.
If, however, you notice that the time and effort given to prototyping surpasses the expected timeframe, it is worth checking up on them to understand their thought process. Maybe the problem is more difficult than anything they have experienced so far. They might accept that they didn’t grasp certain aspects of the problem well, or everything might be happening correctly, but they are going beyond what they are building.
Based on the opinion of top software development companies, prototyping is a normal and healthy pattern. The key is in perceiving when it’s gone on for a very long amount of time or has exceeded the normal time and effort. Make sure that the level of time prototyping is in alignment with the significant level of business risk and the amount of value you expect from the feature.
#2 Perfectionism
Perfectionism refers to a high code churn rate in the mid-to-late stages of the sprint or project once the work is already suitable for production. This incident occurs when a developer’s definition of “good enough” is not aligned with the organization’s standard. Frequently returning to the code to rewrite it without adding much value to the existing code can result in detrimental returns. Generally, the developer’s time can be invested elsewhere.
Solution
- Make a distinction – Does the work fit with team standards when it was checked for the first time? Is this extra work a result of feedback from the review process, or is it of massive benefit to the original code? (If this is the case, that’s great! If engineers are continuously taking feedback from the review process and enhancing their code, that’s something to appreciate.)
- A high code churn rate translating into a release could mean that the release is at risk. Refining code excessively just before the deadline could be an indication that the release needs to be postponed.
- Be aware of what “done” is. Compare the original requirements with what the team actually delivered. If a developer spends too much time reworking or refining code beyond what the project requires, ask a more senior developer to evaluate what ‘good enough’ means for the project.
#3 Difficult Problems
When experiencing a very challenging issue, a high amount of exploring and backtracking is expected. The key is to start understanding if the problem has gone on for an extended period of time. According to a renowned software development services provider, a high code churn rate can sometimes cause engineers to believe they have fully resolved a problem and even submitted it for review, only to realize later that they need to rework major sections. In such cases, they may need to revisit the specifications, or they may not have fully understood the challenge or the best way to solve it from the beginning
Solution
- Learn to discover when a challenge has gone on too long and be proactive.
- It is preferred to be trained by a senior developer or a team lead instead of a manager. Ask them to pair programs if possible.
- Look for a time slot that works for them and doesn’t impact their workflow. Check if they have the resources they need and what extra ones can be useful for you to deliver.
#4 Vague Requirements
When a developer works with unclear requirements, they count on their best guess to understand and fill any gaps. Needless to say, a few of those assumptions will be wrong and result in a high code churn rate. If the specifications are terribly written or incomplete, the developer may be working on something unbuildable.
Solution
- Go through the requirements to learn if more clarification is required and if edge cases have been perfectly resolved.
- Give an example of what good requirements appear to be. Let them know if they want the project to be delivered quickly. In that case, they can offer clear specifications to expedite the process.
- Schedule a meeting with the product team and demonstrate to them the cost of vague requirements. If you utilize GitPrime, get a chart from the project timeline to show them what engineering throughput looks like to ensure a clean implementation compared to a fuzzy one.
#5 Issues Concerning External Stakeholders
Generally, a high code churn rate emerges as the outcome when working with unclear or indecisive stakeholders. While it may seem harmless, an underconfident stakeholder can cause actual damage to a team, both in terms of morale and progress. And it can lead to annoyance or frustration in the team over time.
If miscommunication between expectations and deliverables causes missing functionality or features, the team will likely experience a significant increase in new work after receiving the updated requirements. If the miscommunication results in code rewrites, developers will notice a sharp increase in code churn. In either case, treat a substantial rise in activity during the final third of a sprint, unless triggered by code reviews, as an indicator that the deadline may be at risk.
If you observe this pattern across multiple sprints with the same team, check with team members to determine whether late-arriving requests are causing this work pattern. As the team identifies, develops, and optimizes solutions, it should gradually reduce the size and complexity of the issues it addresses. A sudden boom in activity, especially in the later stages of a project, appears to be a signal that something new has come in.
Solution
- If a stakeholder is constantly changing their mind post-development has commenced, show them the percentage of effort that goes into rebuilding (generally including time and dollars to clarify the impact of this work behavior).
- Perceive that changing requirements from a product owner can indicate that they lack time or money to do what they want. This is why the concerned development task does not get its full attention until it’s too late. Thus, it makes sense to be empathetic and have a discussion with the manager. The experts at a leading digital transformation company recommend including data in discussions. Doing so helps remove uncertainty about what is happening. It also enables teams to focus on finding effective solutions and resolving the issue moving forward.
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What Are The Top 3 Tools for Measuring Code Churn
1. Git
Git is a free-of-charge and open-source distributed version control system designed to manage everything from tiny to considerable projects with speed and efficiency. It connects with git storage and fetches meaningful metrics for a given time period.
A few of the metrics measured by this tool include:
- Number of lines of code added
- Number of lines of code deleted
- Number of lines of code modified
- Number of files changed
- Total code churn
2. GitHub
GitHub is a source code management tool that allows your development team to monitor, manage, and review the changes made in the codebase. This particular tool comes in both free and paid versions.
While it has the basic feature of source code management, the paid variant ships with advanced features, like GitHub Copilot. According to a leading software development services provider, Copilot is an AI-powered tool. It helps developers write better code by providing intelligent recommendations.
3. Jira
Jira is a change management tool. It helps organizations transition from conventional change management processes to a modern and more efficient change management approach. It makes sure that you record, evaluate, approve, and act on change requests. Having this tool at your disposal helps you schedule and track ongoing changes. It also makes it easier to mitigate code churn risks and streamline change management processes. Additionally, its automation feature helps calculate the risk level of every change request. It also assigns the appropriate risk value to each request.
You can also take advantage of Jira to:
- Categorize a change request as emergency, normal, or standard.
- Route change requests down the standard Jira workflow, such as pre-approvals required for ordinary changes and extra workflows required for high-risk changes.
- Inform concerned stakeholders about high-risk changes that need further review.
How to Calculate Code Churn Rate?
For code churn calculation, all you need to do is apply a very simple formula. Let’s say at the start of a month, a mobile app has 20,000 lines of code. During the month, developers have:
- Added 4,000 lines of code
- Changed 1000 lines of code
- Deleted 600 lines of code
Now, to calculate the code churn rate, all you need to do is:
Calculate all the lines of code changed:
Total lines changed
= 4,000 (added) + 1000 (modified) + 600 (deleted)
= 5,600 lines
Calculate the code churn rate:
(Total lines changed / Initial lines of code) * 100
= (5,600 / 20,000) * 100
= 28%
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Conclusion
The insights from code churn metrics significantly affect the overall effectiveness of the final software. And your churn rate will tell that fable over time. Please remember that churn rate is not just a number. It gives you a reality check on how your project is progressing. It also helps you determine whether you need to take timely corrective action while you still have the opportunity.
Eventually, every software engineer aims to develop a high-quality software product. It should meet both technical and user expectations. Tracking and managing churn rate plays a crucial role in achieving this goal. If you want to learn more about efficient software development services and software quality metrics, consider consulting a leading digital transformation company. It can help you improve software quality while keeping overall development costs under control.
Frequently Asked Questions
Code churn rate measures how frequently developers modify, rewrite, or delete code within a specific period. It helps engineering teams identify unstable code, improve software quality, and optimize development processes.
Common causes include changing business requirements, unclear project scope, poor code reviews, inadequate planning, technical debt, frequent requirement changes, and insufficient testing during development.
Not necessarily. Higher churn can be expected during the early stages of development or major feature releases. However, consistently high churn in mature projects may indicate quality issues, unstable requirements, or inefficient development practices.
Organizations can reduce code churn by improving requirement gathering, adopting Agile planning, conducting regular code reviews, strengthening automated testing, maintaining coding standards, and encouraging better collaboration across development teams.
A professional software development partner helps establish efficient engineering workflows, improve code quality, reduce technical debt, and implement best practices that support scalable and maintainable software products.
