Goodhart’s Law:
Once a social or economic indicator or other surrogate measure is made a target for the purpose of conducting social or economic policy, then it will lose the information content that would qualify it to play such a role.
Translation: once people know what you’re measuring, they start to game the system. Read about it here.
well, the correct solution (not mentioned in the post) is to construct more robust algorithms, i.e. that place more weight on ungameable data (similarly attribute little weight to questionable data), that behave well at the edge, and that penalize unwanted behaviour.
the laws of biology/physics/chemistry serve as good prototypes. eg you can’t game gravity, or death, or energy conservation.