What has come to be called “Campbell’s Law,” named for the American social psychologist Donald T. Campbell, holds that “[t]he more any quantitative social indicator is used for social decision-making, the more subject it will be to corruption pressures and the more apt it will be to distort and corrupt the social processes it is intended to monitor.”9 In a variation named for the British economist who formulated it, we have Goodhart’s Law, which states, “Any measure used for control is unreliable.”
