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10 facts about code reviews and quality

This is a short and sweet story about important facts to know and share about code quality and code reviews. You can also read more about this in our new ebook. Join the discussion on reddit and hacker news.

680 companies were asked about their code quality and code review practices. Below are some of the learnings.

A Soviet inspector reviews a BGM-109G Tomahawk ground launched cruise missile.

The facts

Fact 1:

We spend a significant amount of time reviewing code. In fact on average, we spend 5 hours per week reviewing code or 12.5% of our week looking at code.

Fact 2:

As a developer, spending more than a day a week reviewing code doesn’t correlate with improvements in perceived code quality OR in more time shipping new features (as opposed to fixing bugs or paying back tech debt).


Code Quality Score vs. Hours per week spent on code reviews

Diminished returns: spending more than a day per week reviewing code does not correlated with better perceived code quality

Fact 3:

45% of developers say ‘Lack of Time’ is the real obstacle to reviewing code while 34% say ‘Pressure to Ship’.

Fact 4:

72% of developers say their code reviews are blocking (don’t ship a line of code without being reviewed).

Fact 5:

66% of developers require 1 person to approve their pull requests. 25% require 2 people. Less than 5% require more than 2.

Fact 6:

53% of people monitor code coverage but 65% don’t have a minimum threshold of code coverage to approve a pull request.

Fact 7:

29% of developers say the biggest problem in their project is “Workload” while VPs of Eng and Directors say “Delivery speed”. The third biggest problem for developers is “Management


Who reviews code?

Who gets to review code? Two thirds of companies prefer the all hands on deck approach to code review.

Fact 8:

Regarding who gets to review code, having everyone in the team do it is the most common practice. Other alternatives are having owners of projects or modules or having senior developers review most of the code.

Fact 9:

Stricter code reviews lead to less time fixing bugs and more time delivering new features. Less strict code reviewers spend 31% of their time fixing bugs whereas stricter reviewers spend 24%. Regarding time focusing on new features: 43% and 54% corresponding.

Fact 10:

Developers spend 45% of their time fixing bugs or addressing technical debt vs of building new features.


Time spent on average per activity during development

Time spent on average per activity during development

Thanks for reading! You can also read more about this and other great learnings in our new ebook about code reviews:


Click to get the ebook

Click to get the ebook

Until next time!



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