The 'Fitness Function' Failure: Why Compound Metrics Don't Work
Carr shares an Amazon idea that never worked — the 'fitness function,' which blended a team's five or six most important metrics into a single weighted index. He explains that compound metrics obscure cause and effect, making it impossible to learn which actions drive results, and now actively discourages companies from building them.
- The fitness function munged multiple important metrics into one weighted index
- Compound metrics become meaningless because you can't see which action drives which output
- The fix is to break each metric out and manage it individually
- There's usually one metric that impacts the bigger goal most, so you end up working on that anyway
“so I today I discourage teams and companies from creating any sort of compound metrics I've done that once and it was a terrible idea”