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Rework Rate ​

Definition: Rework Rate measures the percentage of code that is changed within a short period (e.g., 2-3 weeks) after it was first written. It quantifies the amount of "wasted effort" spent modifying recent code, often due to bugs, unclear requirements, or integration issues.

Why It Matters ​

Rework Rate is a powerful measure of development quality and efficiency. A high Rework Rate indicates that work is not being done correctly the first time.

  • Quantifies Wasted Effort: It directly translates process problems into a measure of inefficiency. A 20% Rework Rate suggests that one-fifth of the team's recent coding effort was spent fixing or changing brand new code.

  • Indicates Quality Issues: High rework is often a symptom of insufficient testing, poor code review, or unclear acceptance criteria, leading to bugs and misaligned implementations that must be fixed immediately.

  • Highlights Planning Deficiencies: If rework is consistently high, it can signal that requirements are not being defined clearly enough before development begins, causing developers to build the wrong thing.

How to Measure It ​

Rework Rate is calculated by analyzing version control history to identify code that was recently changed.

Rework Rate = (Lines of Reworked Code / Total Lines of Code Changed) * 100

"Reworked Code" is defined as any line of code that is modified or deleted within a few weeks of its creation.

Interpretation ​

  • Goal: The goal is a low and stable Rework Rate. Some rework is unavoidable, but it should be the exception, not the norm.

  • Investigate Spikes: A sudden spike in Rework Rate after a release is a clear signal that the release had quality problems and should trigger a retrospective.

  • Compare to Churn: While Code Churn looks at long-term volatility, Rework Rate is focused on the short-term quality of new code. A file can have low churn but a high rework rate during its initial development.

Associated Concepts ​