Are we assuming that police arrests and citations for carrying an illegal knife actually reduce or deter knife crime? Because I don't believe that it does.

--Same as you, just using knives as an example because I agree that they should not be illegal. (And a lot more could be said about certain types of knives being illegal and others not and the idea that certain racial groups or gangs might be more likely to carry that certain type, crack vs cocaine anyone?) But you could replace knives with any type of crime.--

But the reality is that we have a system that will over-prosecute and over-charge people for small crimes which causes a disruption to a lower income person's already precarious situation. Putting through a system full of violence, inhumanity, and other people that are in for much worse and then releasing them back to that same community with a do-not-hire sign permanently around their neck (a felony). After which they are likely to turn to crime to survive.

So while I agree that looking at knife crime data would make more sense than looking at arrests in the scope of the data conversation, the idea that heavy handed policing and a messed up "justice" system will likely create negative pressure on the long term for crime in that community, then the data is sort of moot.

Additionally, the conversation in this mini-documentary pointed to the fact that police were/are incentivized (at least in his Detroit precinct) to "get their statistics". So they would gravitate to these poorer, black neighborhoods because they could stop and hassle low income minorities without repercussion a lot easier than a white middle class neighborhood where people were less likely to even be walking outside and more likely to file complaints for police harassment.