The drunkard looking for his keys under the streetlight problem

There is an old joke that goes something like this:

A policeman sees a drunk man searching for something under a streetlight and asks what the drunk has lost. He says he lost his keys and they both look under the streetlight together. After a few minutes the policeman asks if he is sure he lost them here, and the drunk replies, no, and that he lost them in the park. The policeman asks why he is searching here, and the drunk replies, “this is where the light is”.

The productivity of so-called knowledge work is notoriously difficult to evaluate, which is why proxy metrics tend to be used, line of codes of old, story points of this modern fragile age, but these metrics are only at best a weak indicator of productivity and at worse detrimental to productivity but they have a massive upside, namely they are easy to measure and that’s why they keep getting used.

This is what I like to call the drunkard looking for his keys under the streetlight problem and as it happens it’s already been named streetlight effect or drunkard’s search principle, which I’ll have to admit is a bit catchier that my name.