“When a measure becomes a target, it ceases to be a good measure.”

The law is implicit in the economic idea of rational expectations. While it originated in the context of market responses, the law has profound implications for the selection of high-level targets in organizations.[4] Jón Danı́elsson quotes the law as “Any statistical relationship will break down when used for policy purposes”, and suggests a corollary to the law for use in financial risk modelling: “A risk model breaks down when used for regulatory purposes.”

Source: Goodhart’s law – Wikipedia

With the push toward using standardized testing scores, this economic policy could have ramifications on the validity of said test scores.