A team lead is responsible for their team’s input metrics.

These are the controllable metrics that the team has control over.

They need to figure out which input metrics are the most important, how they affect the bigger picture, the system at large, processes, and finally, output metrics — these are things like “new customers,” “existing customer revenue,” and other things we don’t have direct control over.

They need to know their input metrics, keep track of these, create effective ways of measuring them, and continuously improve them.

When they run into something surprising, they should be relentless in figuring out what happened.