Slide 106 ftw.

"Although Goodhart's law has been expressed in a variety of formulations, the essence of the law is that 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. The law was named for its developer, Charles Goodhart (a chief economic advisor to the Bank of England)."