All of Unnamed's Comments + Replies

Goodhart Taxonomy

Adversarial: A college basketball player who wants to get drafted early and signed to a big contract grows his hair up, so that NBA teams will measure him as being taller (up to the top of his hair).

1Ben Pace4yI'm trying to think of a causal goodheart one. A bad one I came up with is that if someone thinks the reason taller people get better careers is because the hiring committe likes tall people, and so the person wears heels in their shoes, then this is a causal godheart because they're trying to win on a proxy but in a way causally unrelated to the goal of having a good career. But everyone knows the true causal story and don't make this mistake, so it's not a good example. Is there a causal story people don't know about? Like perhaps some false belief about winning streaks (as opposed to the standard Kahneman story of regression to the mean).
3jefftk4yAnd: -- http://www.nytimes.com/2003/06/15/sports/basketball/tall-tales-in-nba-dont-fool-players.html
Goodhart Taxonomy

Height is correlated with basketball ability.

Regressional: But the best basketball player in the world (according to the NBA MVP award) is just 6'3" (1.91m), and a randomly selected 7 foot (2.13m) tall person in his 20s would probably be pretty good at basketball but not NBA caliber. That's regression to the mean; the tails come apart.

Extremal: The tallest person on record, Robert Wadlow, was 8'11" (2.72m). He grew to that height because of a pituitary disorder, he would have struggled to play basketball because he "required l... (read more)

4Scott Garrabrant4yGreat example! It would be really nice if we had an example like this that worked well for all four types.