In the police world, there are good arrests and better arrests, but there is no such thing as a bad arrest. In recent years, measures of “productivity” have achieved an almost totemic significance. And because they are so easy to count, arrests have come to outweigh more important but harder-to-quantify variables such as crimes prevented, fights mitigated, or public fears assuaged.
There’s an argument that putting pressure on rank-and-file officers to make lots of arrests is a good thing. After all, we pay police to arrest criminals. But there’s a difference between quantity and quality. Quantity is easy to influence, and the rank and file can easily increase their output of discretionary arrests for minor offenses like loitering, disorderly conduct, and possession of marijuana. They are also influenced by what is known in New York as “collars for dollars”: Arrest numbers are influenced by the incentive of overtime pay for finishing up paperwork and appearing in court.
Police would love to arrest only “real” criminals, but that isn’t easy. It’s difficult to find a good criminal. There’s never a felon around when you need one. Fishing for low-level drug arrests is a far easier way to generate overtime.