The Ultimate Checklist For High Quality Code Reviews

Did you know that code reviews are the single best thing that a company can do to improve code quality?

SmartBear research of over 1,000+ developers found that code reviews deliver powerful benefits beyond just catching bugs. The top 3 benefits from code reviews, as found in the SmartBear research, are:

1. Improved code quality and software delivery performance – by reviewing code consistently, teams can catch bugs early to save time later. DORA found that teams with faster code reviews have 50% higher software delivery performance
2. Knowledge sharing — team members taking part in code reviews means they're collaborating more, and distributing knowledge, avoiding knowledge silos.
3. Learning and development — code reviews can be a great learning opportunity for both junior and more experienced developers. Experienced developers provide mentorship and juniors improve their problem-solving and technical skills. SmartBear's research showed 64% of survey respondents use code review as a training resource for new developers

The data shows that having clear code review guidelines correlates with increased team satisfaction, and in particular, remote teams benefit from structured code review processes.

What makes these findings especially relevant?

In today's world of distributed teams and complex compliance requirements, a solid code review process isn't just nice to have — it's essential for team success.

Sections:

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Code reviews are a collaborative process where developers examine each other's code changes before they move into testing or production. Think of it as a quality checkpoint where the team can catch potential issues, share knowledge, and ensure code maintainability.The process typically works like this:

• When a developer completes a code change, they create a pull request for their teammates to review.
• Reviewers examine the code for potential bugs, security issues, and alignment with team standards.
• This back-and-forth discussion helps catch problems early, when they're easiest and least expensive to fix..

Reviews are most effective when conducted by developers who aren't directly involved in the project - this outside perspective helps ensure the code is clear and maintainable for everyone, not just those familiar with it. Code reviews should happen throughout development, with one exception: small, experimental projects meant to be quick and temporary. Even under deadline pressure, we encourage still maintaining code reviews. It could be the difference between a major system outage, and not!

‍Most teams follow a standardized checklist during reviews. This helps catch common issues and validates that code aligns with company standards, covering both technical correctness and coding style.

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While there are different approaches to code reviews, and each team might have their own styles, here are a few guidelines as to how you can make code reviews both fast and effective:

• A human is on the other side – Behind every line of code is a person who wrote it with care and consideration. The way we communicate in code reviews directly impacts team relationships and morale. Clear, kind communication builds trust and encourages continuous improvement.
• Seek to understand – When code isn't immediately clear, start by asking questions rather than making assumptions. Understanding the author's intent often reveals important context that isn't visible in the code alone. Schedule a quick call for complex changes - a 15-minute conversation can save hours of back-and-forth comments.
• Follow the style guide – Style guides exist to eliminate unnecessary debates and streamline decision-making. Automate style enforcement through linters and formatters to keep reviews focused on substance rather than syntax. When style guides fall short, work with your team to update them - living documents serve teams better than rigid rules.
• Software design principles – Code reviews should emphasize sound engineering principles over personal preferences (see example from Google Tech Dev Guide). Accept that perfection isn't the goal - instead, focus on consistent improvement. Approve changes that move the codebase in a better direction, even if they're not flawless.
• Fallback consistency – Review every line with equal attention, and when no clear rule applies, lean toward consistency with existing patterns. This creates a more maintainable codebase while respecting established team practices.
• Frame feedback as requests, not commands – Present suggestions as opportunities for discussion rather than mandates. This approach acknowledges that there are often multiple valid solutions to a problem. Consider customer needs and development velocity alongside technical perfection.
• Show rather than tell – Concrete examples make complex feedback more actionable and easier to understand. When suggesting an alternative approach, include a snippet of code that illustrates your thinking.
• Avoid using "you" – Keep feedback centered on the code itself rather than the person who wrote it. This creates a psychologically safe environment for everyone to share work and receive feedback.
• Learn from the author – Every code review is a two-way learning opportunity. Whether you're new to the team or a seasoned veteran, approach reviews with curiosity. Authors often bring fresh perspectives and novel solutions that can benefit the entire team. Stay open-minded to any feedback that is shared.
• Don’t force code reviews – Despite all the good things we’ve mentioned — you don’t always need it! Remember that you ultimately want to deliver value at a high pace, and that a two-line copy change can be reviewed after code has been merged as well.

Note: GitHub commonly refer to Pull-Requests (PRs) as changes to a code-base, whereas Google tend to use Change Lists (CL). For most intents and purposes, they refer to the same thing.

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‍1. Design

‍Great code starts with solid architecture. During reviews, assess how well the code aligns with design principles and whether it fits naturally within the existing system. This foundation determines how maintainable and scalable the code will be.

• Check if the code follows SOLID principles and your organizational architecture guidelines
• Evaluate abstractions and identify if functionality belongs in the codebase or a library
• Verify seamless integration with existing systems without creating unnecessary dependencies

2. Functionality

‍The code must work as intended, not just in theory but in practice. While functional correctness is primarily the developer's responsibility, reviewers play a crucial role in identifying edge cases and potential issues — ultimately you want to ensure the code is doing what you intended it to.

• Run the code and see if it works as expected  (you could request a demo too, if needed!)
• Review test coverage for critical flows and edge cases (this is key to preventing regressions
• Check error handling, concurrency issues, and user-facing impacts

3. Complexity and Readability

‍Simple, readable code is easier to maintain and less prone to bugs. Focus on identifying areas where complexity can be reduced while maintaining functionality.

• Look for unnecessary complexity at line, function, and class levels
• Confirm adherence to style guides and local code conventions (e.g., indents)
• Check that the organization of the code makes the code itself easy to understand

4. Security

‍Security shouldn’t be an afterthought - it needs to be built into every piece of code we write. Look for potential vulnerabilities and ensure proper security practices are being followed.

• Check for common security vulnerabilities such as injection risks and unauthorized access
• Verify secure data handling and protection against leaks
• Ensure security best practices are followed throughout the code (for example, check out Atlassian’s DevSecOps)

5. Naming

‍While seemingly minor — clear, descriptive naming is fundamental to code readability. While naming is challenging, it's worth the effort to get it right as it significantly impacts future maintenance.

• Verify names are descriptive and follow team naming conventions
• Check for overly verbose or unnecessarily abbreviated names
• Ensure naming consistency across similar concepts

6. Documentation and comments

‍Good documentation explains the why, not just the what. It helps future developers understand the context and reasoning behind implementation choices.

• Categorize comments into BLOCKER, FAST FOLLOW, and NIT enabling teams to prioritize effectively
  • BLOCKER — must be addressed before this PR can be merged
  • FAST FOLLOW — must be addressed, but optionally via a follow-up PR
  • NIT — feedback that the author can take or leave, or an opportunity to open up a discussion on team norms.
• Check that relevant documentation is updated and remove outdated comments

7. Code Duplication

‍Duplicated code increases the maintenance burden and the risk of inconsistencies. While some duplication might be warranted, it should be intentional rather than accidental.

• Identify repeated code blocks that could be consolidated
• Check if existing libraries or functions could be used instead
• Look for opportunities to reduce redundancy without over-abstracting

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You can't manage what you're not measuring – with Multitudes, you can measure key metrics that indicate whether your code review process is lagging, and what the potential blockers are.

But don't take it from us – one of our customers, Vital, decreased their review wait time by over 40% using Multitudes' insights.

‍When Engineering Manager, Will, noticed that his team's Time to Merge had increased to 2-3 days (it would normally be under one day), he dug deeper into the data.

He noticed that, with the increase in Time to Merge, the team also had much larger PR sixes. Studies from Google have found that as the size of PR increases, the number of useful comments decreases. What’s more, the review latency increases, so the smaller PRs are correlated with better quality and faster delivery.

When he discussed this with the team, it came to light that people had different expectations about how to write and review PRs. They made two key changes:

1. In their PR norms, they set a goal to write shorter PRs
2. In their code review documentation, they set expectations around how to have notifications configured, how quickly responses were expected and what kind of feedback should be given in order to speed up Review Wait Time.

The result? During the week following the team discussion, the engineering teams started to respond more quickly to review requests. Review Wait Time reduced by 41% during this period, and following, Time to Merge also dropped across all of Vital's teams - ranging from 74% all the way to a 97% decrease!.

You can read the full story here.

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Start measuring your development team's delivery performance, so you can see how they're going with code reviews and the impact this is having on delivering value.Multitudes integrates with your existing development tools, such as GitHub and Jira, to provide insights into your team's productivity and collaboration patterns.With Multitudes, you can:

• Automatically track all key engineering performance metrics like Change Lead Time and Deployment Frequency
• Get visibility into work patterns and where the team’s time went, e.g. into feature work vs. maintenance work and bug fixes
• Identify collaboration patterns and potential knowledge silos within your team
• Understand individual and team health through metrics like out-of-hours work, incidents, and meetings
• Get nudges via Slack about blocked work and who might need more support, sent just in time for your next stand-up, retro, or 1:1

Our clients ship 25% faster without sacrificing code quality.

Ready to unlock happier, higher-performing teams?

‍Try Multitudes today!

‍The insights above come from both our internal Multitudes team and resources published by industry leaders who’ve shared their thoughts like Google, Gergely Orosz (Pragmatic Engineer), and also Microsoft.

A huge thanks to the Multitudes engineering team for sharing how they approach code reviews. In particular, thank you to @Kevin Chan and @Vindhya Joseph for sharing their own personal approaches!