I have mentioned before - I hate Goodhart's law. It makes no sense. There is no example that is a good measure but a bad target.
The canonical example I have heard is hospital emergency rooms that started to be measured by wait times, so they refused to admit patients until staff was ready to receive them, literally having ambulances circling around the block. This was supposed to be a "good measure turned into bad target" situation, but of course it makes no sense. What really changed was the locus of evaluation from the patient that evaluates his end-to-end emergency care experience on many criteria, including, but not limited to, emergency room wait times, to a bureaucrat who just evaluates the hospital myopically on 1 metric.
It is always the myopia of singling out this measure/target that is bad, throwing off all other tradeoffs and considerations, not the actual desire to improve the measure/target.
The canonical example I have heard is hospital emergency rooms that started to be measured by wait times, so they refused to admit patients until staff was ready to receive them, literally having ambulances circling around the block. This was supposed to be a "good measure turned into bad target" situation, but of course it makes no sense. What really changed was the locus of evaluation from the patient that evaluates his end-to-end emergency care experience on many criteria, including, but not limited to, emergency room wait times, to a bureaucrat who just evaluates the hospital myopically on 1 metric.
It is always the myopia of singling out this measure/target that is bad, throwing off all other tradeoffs and considerations, not the actual desire to improve the measure/target.