Code review best practices for quality and collaboration

In the rapidly evolving landscape of software development, the distinction between good and exceptional often hinges on one key process: code reviews. When your team is driving hard towards the next release, thorough and efficient code reviews make all the difference.

And while every engineer and QA team understands the importance of these reviews, perfecting your code review is another challenge. Implementing code review best practices will help you create a collaborative environment and maximize the value of your code reviews.

1. Set up a comprehensive review checklist

Let’s say you and your QA team just finished the smoothest code review you’ve ever experienced. Your team was in sync, feedback was clear and actionable, turnaround was quick, and you were able to deploy sooner than expected. That’s the dream, isn’t it?

But if your code review process isn’t repeatable, that one perfect review doesn’t do much good for your overall code quality and efficiency. For consistent reviews, a code review checklist that’s designed to work with your internal process is key. It acts as an anchor by:

  • Ensuring uniformity with consistent standards, regardless of the reviewer
  • Reducing oversights with clear guidelines; and
  • Accelerating the review process by laying out a clear path for streamlined evaluations

Start with the basics, then evolve. Engage your team (code authors and reviewers), encourage feedback, and periodically refine based on insights and industry advancements.

2. Set goals and metrics

Any team, no matter how skilled, will fail if each person is running toward a different goal. Whether you’re confirming correct functionality or ensuring compliance, it’s crucial to set goals up front to keep your team focused on delivering the same outcomes.

Once you’ve established your goals, identify objective metrics to gauge the effectiveness of your reviews, how efficient (or inefficient) your process is, and whether or not your feedback loop is helping you identify and prevent recurring issues.

External metrics  — like a 20% reduction in customer support tickets, for instance) — should be tracked alongside internal metrics such as inspection rate, defect rate, and defect density.

Inspection rate is the speed at which code is reviewed (i.e., lines of code per hour). Aim to keep it below 500 lines of code (LoC) per hour to ensure thoroughness, but if it takes too long, that might be a sign of readability issues.

Defect rate is calculated by dividing the number of defects found by the number of hours spent on a code review. A higher defect rate might be a good thing, signifying that your team is exceptionally vigilant. A low defect rate might signal that your reviewers need better testing tools or support.

Defect density is calculated by dividing the defect count by thousands of lines of code (kLOC). If the defect density is high, this could reveal areas that need extra attention as well as indicate where your authors may need additional training.

Tracking these metrics with a QA test management platform will help you increase efficiency, weigh the impact of code changes, and make better predictions for resource and time allocation in the future.

3. Strike a balance between speed and thoroughness

The depth and duration of a code review plays a pivotal role in ensuring both its efficacy and efficiency. Over-investing time can diminish returns and strain resources, but thoroughness is still crucial.

Set an ideal inspection rate goal

The inspection rate we mentioned above is worth emphasizing again. Faster rates can lead to oversights, while slower rates may indicate over-analysis or challenges in understanding the code. Monitor and adjust based on this metric to continuously streamline the review process.

Work in short stints

Continuous prolonged scrutiny can lead to cognitive fatigue, diminishing the reviewer's ability to spot issues. If you’re a reviewer, take a break every hour and come back with fresh eyes.

Customize for your team

Adapt these general guidelines to work with your team's unique dynamics and your product. For example, if your team has a mix of senior and junior developers, timeline expectations may vary based on which team members are involved. Or, if some projects involve intricate code, they might require slower inspection rates and longer review times.

4. Establish expectations for authors and reviewers

A structured, effective code review process goes beyond merely skimming lines of code. Code review best practices encourage both authors and reviewers to comprehend the review's intricacies and their individual roles within it. To yield meaningful outcomes, both parties need to approach feedback with an honest but respectful attitude.

Start by establishing what code review feedback does and does not cover. Great code reviews concentrate on the specifics of the code’s logic, algorithms, and potential edge cases. Reviewers should avoid analyzing an author’s coding style and instead investigate if the code is efficient and adheres to documented guidelines.

It’s also key to define the responsibilities of authors and reviewers.

The author’s primary role  is to submit clean, understandable code.  It’s the author’s responsibility to:

  • Perform a self-review to catch any obvious mistakes before submission;
  • Annotate the code with comments to guide reviewers about particular solutions or potential areas of concern; and
  • Embrace feedback and be willing to make revisions based on constructive critiques

Reviewers act as a second pair of eyes, ensuring the code aligns with best practices, is bug-free, and has maintainability. It’s their responsibility to:

  • Understand the problem the code is solving and its overall logic; and
  • Give feedback by clearly communicating findings and suggestions for improvements

Consider rotating your reviewers to ensure code is scrutinized from multiple angles. A database expert might spot inefficiencies in a query, whereas a security expert might find vulnerabilities. Not only will diversification prevent bias and bring varied problem-solving approaches and insights to your reviews, but it will also increase your chances of identifying oversights.

Set up a system where reviewers rotate regularly. Encourage team members to occasionally seek reviews from peers outside their regular rotation, as well.

5. Provide clear and actionable feedback

When it’s time to provide feedback, be concrete and specific. Vague comments like “this is confusing” don’t give the code author any guidance on what actually needs to change. More specific feedback like “This variable name does not clearly communicate what it represents, can we use a more descriptive name?” is far more helpful.  

More precise feedback helps improve your code review process over time. Be sure to document constructive feedback for your team. Documentation helps you identify recurring mistakes alongside the actionable feedback on how to fix them — and, ideally, help prevent similar issues in the future.

6. Use tools and automation

While human intuition and expertise play an undeniable role in code reviews, automated tools bring a level of precision, speed, and consistency that's hard to match. While you should never rely solely on automation, the integration of these code review tools not only optimizes the review process but also acts as a first line of defense against common errors.

Advantages of automation include:

  • Consistency: Automated tools scan code based on a set of defined rules, ensuring consistent checks every time.
  • Efficiency: Speed is a hallmark of automation. These tools can swiftly scan vast codebases, flagging potential issues in minutes.
  • Unbiased evaluation: Automated checks are devoid of personal biases, ensuring objective and consistent evaluations.

Take a look at your criteria, such as language, scale, and common challenges you need a tool to address. Then, research a couple tools to demo.

We suggest looking for an end-to-end test management platform that allows for both manual and automated testing. That way, as your team grows, software evolves, and you inevitably abandon one code review tool for a new one, you’ll have a home base that integrates with all major issue trackers.

7. Add lightweight code reviews

While code review best practices call for in-depth reviews for complex codebases or critical applications, there are instances where lightweight reviews are more efficient and equally effective.

Unlike typical code reviews, lightweight code reviews are quick checks that focus on the most salient points of a piece of code without diving deep into every detail. The main goal is to identify any blatant errors or major inconsistencies. Lightweight reviews may be suitable for small UI changes, an isolated bug, or if a section of code or a particular contributor has a history of high-quality submissions.

Since lightweight reviews are faster than traditional reviews, they’re ideal for agile settings where changes are incremental or those with frequent release cycles. They can be done asynchronously, making them adaptable to diverse team structures and schedules, and they minimize the cognitive load on reviewers, allowing them to cover more ground in less time.

These lightweight code reviews are where the tools mentioned above come in handy. Tools scan to catch basic errors and allow your reviewers to put their energy elsewhere.

Assess your current code review process

Take a look at your current review process and tools. Which of these code review best practices have you already implemented? Where do you fall short? Your next step should be to identify ways you can improve your processes.

As you refine your approach, don't forget the impact that the right tools can have. Explore the advantages of an end-to-end test management platform that offers integration with major issue trackers and both manual and automated testing capabilities. With best practices and the right tools in place, your team will not only be more efficient, but also more flexible and collaborative.

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