Goodhart's Law

Goodhart's law is an adage named after British economist Charles Goodhart, who advanced the idea in a 1975 article on monetary policy in the United Kingdom, Problems of Monetary Management: the U.K. Experience:[1][2] "Any observed statistical regularity will tend to collapse once pressure is placed upon it for control purposes." In a paper published in 1997, anthropologist Marilyn Strathern generalized Goodhart's law beyond statistics and control to evaluation more broadly. The phrase commonly referred to as Goodhart's law comes from Strathern's paper, not from any of Goodhart's writings: "When a measure becomes a target, it ceases to be a good measure." (metric, feedback) https://en.wikipedia.org/wiki/Goodhart%27s_law