[softwaredoug]

I have a better idea, measure how good you are at turnover. How negative is it when someone leaves? How easy is it for someone to join and be productive?

Well, specifically, you can measure onboarding, which is a proxy:

How quickly can someone get started on a feature and ship it to production? How obvious is it for them to follow your teams procedures, guardrails, tests, review processes, etc and go?

Maximizing this means maximizing the available colleagues that can work on your codebase and sets up a positive culture of enablement. It means maintaining your code is not an inscrutable mess.