Why Police Officers Rarely Change Jobs (theatlantic.com)

Micro-summary: Very low turnover has some benefits...but also seems related to problematic police behavior.

> What the researchers found is that when police are stuck in the same law-enforcement agency, stuck with the same peers and commanding officer, they are also more likely to adhere to the “blue wall of silence”—an unwritten code to never implicate another officer of wrongdoing.

That's why other services have transfers and everyone changes posts every few years.