According to the physics arXiv blog
It’s not so hard to see that a new position in an organization requires different skills, so the competent performance of one task may not correlate well with the ability to perform another task well.
But is there a better way of choosing individuals for promotion? It turns out that there is, say Pluchino and co. Their model shows that two other strategies outperform the conventional method of promotion.
The first is to alternately promote first the most competent and then the least competent individuals. And the second is to promote individuals at random. Both of these methods improve, or at least do not diminish, the efficiency of an organization.