Named after economist Charles Goodhart, this law warns that once you start optimizing for a specific metric, people will game the system to hit that metric—often at the expense of what you actually wanted to improve.
In Software
- Lines of code as productivity metric → bloated code
- Number of bugs fixed → splitting tickets, ignoring root causes
- Code coverage % → meaningless tests written just to hit the number
The lesson: measure outcomes, not outputs, and use multiple complementary metrics.