You would need figures on convictions in the different jurisdictions to get a gauge on what is a reasonable unfounded rate.  You can't assume that any particular not founded rate is what should be expected until you have done the research.  If jurisdictions with low unfounded rates also had low conviction rates, that would suggest they are charging too often. If conviction rates were similar across the board that would suggest that either the police are doing a good job or that more charges could be laid. The two New Brunswick towns would make a good initial comparison. In the case of smaller jurisdictions, you might also need to know how many reports were at issue.