Campbell's Law is the observation that once a metric has been identified as a primary indicator for success, its ability to accurately measure success tends to be compromised.

Here's an example:

Let's say the battalion commander is a hardcore distance runner and thinks a fast run time is the tell-tale sign of a promising leader, since running requires self-discipline, self-motivation, and endurance. One of the PLs in the battalion finds out about this, and dedicates all his free time to running in order to get that fast run time on the APFT. The thing is, the PL is a lazy and incompetent dirt-bag of an officer. But, he runs super fast, so the BC thinks he's a top performer and gives him a positive OER.

Where else have you seen the "if we check these boxes or do well in these few areas, we're good" mentality?