Code churn breakdown

Code can be broken down into 4 sections:
  1. New Work: Code that is newly added and not replacing/rewriting existing code.
  2. Refactor: Code that is modified after 21 days. This is usually an acceptable change needed for maintenance and is therefore separated out from code churn so as not to raise flags.
  3. Churn: Code that is deleted/rewritten within 21 days of merging is called code churn or rework. 
  4. Helping Others: code that is replaced by engineers other than the author of the original code within 21 days of authoring. This is helps you measure to what extent developers are helping their team mates to improve code quality and delivery.