Product teams are usually good at defining what they want to improve: paid conversion, engagement, churn, search success, or transaction completion. The harder question is not what to optimize. It is: what behavior must change elsewhere in the system for this metric to improve?

Product metrics do not move on their own. They move because user behavior changes. And when a team changes incentives, friction, defaults, timing, visibility, or access, it rarely changes only one behavior. Move the paywall earlier and conversion may rise, but the composition of paying users may change. Send more notifications and weekly activity may increase, but so may fatigue. Change search ranking and CTR may improve while discovery quality declines.

The metric improves, but the mechanism that produced that improvement may create damage elsewhere.…