So much this. I'm an advocate of performance metrics being _measured_ and tracked over time, but very careful about setting performance _targets_. It's the la

So much this. I'm an advocate of performance metrics being _measured_ and tracked over time, but very careful about setting performance _targets_. It's the latter that tends to cause the dysfunctional behaviour - it's Goodhart's law [0] in action. When it is required then focusing on user value can help: e.g. "<x> seconds to user login being available" rather than "...page loaded". There's still the question of absolute numbers rather than statistical distributions, but that's another topic. [0] https://en.wikipedia.org/wiki/Goodhart%27s_law https://en.wikipedia.org/wiki/Goodhart%27s_law