Code Change Rate

DEFINITION

Code change rate is the percent of code changed during the review cycle. High code change rates indicate that the original code and subsequent updates did not meet expectations. This may be due to poor code quality and/or unclear or shifting project requirements.

HOW IT’S MEASURED

Code change rate is the difference in the count of lines changed between opening and merging a pull request:

Code change rate = | LoC changed at open - LoC changed at merge | ÷ LoC changed at open × 100%

For example, let's say a developer opens a pull request that changes 200 lines of code. During the review process, the pull request is updated several times based on feedback from other developers. When the pull request is finally merged, it changes 250 lines of code. In this scenario, the code change rate is 25%, calculated as: 

Code change rate = | 250 LoC changed - 200 LoC changed | ÷ 200 LoC changed × 100% = 25%.