Goodhart's Law

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

M. Strathern, “Improving ratings”: audit in the British University system,
European Review 5, 1997, 305–321.

We see, all too often: universities manipulating students’ data, class sizes, etc. in order to improve their rankings; publishers and editors manipulating Impact Factors.

Relying on superficial measures virtually guarantees that they will be manipulated and abused.

Douglas N. Arnold and Kristine K. Fowler wrote an interesting article on the Impact Factor: Nefarious Numbers, Notices of the AMS, 58 (3), March 2011, 434–437.