You are still claiming that crime is conserved. It's not possible, even likely, that a reduced cost-benefit for committing crime shifts preferences toward some non-criminal activity with a more attractive risk-reward profile?

Conservation of crime isn't a claim I made and it isn't relevant to my comment.

If ShotSpotter were successful, crime would move to a different area and/or go down. Arrests would be made, so it's impossible to assume crime rates wouldn't change in that scenario.

Neither happening in correlation with ShotSpotter installation, which is one way we know these tactics don't actually work.

There are far too many confounds to draw a conclusion like "these tactics don't actually work." Speeding up police response to gunfire isn't going to have a measurable impact if the police aren't actually allowed to do anything when they get there, except maybe call the paramedics.

We know at least one of the tactics that does work, because Mayor Bloomberg and the NYPD provided demonstrative proof (and saved thousands of lives by drastically reducing murders). However, that also relies on Bayesian priors (or is it racism?) and thus has become unfashionable amongst the current ruling urban elite. It is highly plausible that a technology like ShotSpotter would be highly effective making such preemptive interventions more data driven and effective.

Unfortunately, the ideological blinders many people choose to wear around criminology really makes it difficult to constructively discuss or address. After all this study is trying to present, in a weaselly way, the claim that ShotSpotter actually increases shootings. I'd love to hear the proposed mechanism for that. I'm sure it's something that makes superstition look sensible.