Tyler Cowen points us to a study from last year which concludes that police officers become “less productive” as they gain experience. Here’s the abstract:
This study analyzes two decades of data from a municipal police agency and describes the average patrol officer career productivity trajectory. We find that declines in productivity begin immediately after the first year of service and worsen over the course of officers’ careers. After their 20th year, patrol officers generate 88% fewer directed patrols, 50% fewer traffic warnings, 58% fewer traffic citations, 41% fewer warrant arrests, and 57% fewer misdemeanor arrests compared to officers with 1 year of experience. Using a patrol officer productivity metric called Z-score per Productive Time (Z-PRO), we estimate that each additional year of service decreases an officer’s overall productivity by about 2%. Z-PRO also indicates that after 21 years of service, an average officer will be approximately 35% less productive overall than an officer with 1 year of service.
There’s an issue of framing here: What is the “proper” level of productivity for a police officer? Perhaps the real issue is that newish police officers are overzealous. They’re eager to ticket anyone going 6 miles over the speed limit. They arrest anyone hanging out on a corner who turns out to have a joint in their pocket. Etc.
It’s not necessarily the case that more is always better. To really judge this stuff, you’d also need to measure the quality of arrests and traffic citations in some way. It’s possible that older officers arrest less because their experience tells them it’s better to let the small stuff go, but have a better eye for genuinely dangerous behavior.
Then again, maybe they just get lazy.