The American social scientist Donald T. Campbell stated a rule in 1976: “The more any quantitative social indicator is used for social decision-making, the more apt it will be to distort and corrupt the social processes it is intended to monitor.”
He applied it to schools: “when test scores become the goal of the teaching process, they both lose their value as indicators” of what students know. Critics later cited Campbell’s law against the federal school programs No Child Left Behind and Race to the Top.