Seems reasonable to me; if there’s the expected amount of crime in an area, then it’s not too worthy of special attention. If there’s a higher than usual amount of crime, then it’s clearly worthy of special attention.
However, if there’s a lower than usual amount of crime, then it’s also worthy of special attention, because that indicates that something odd is happening there (or, it indicates that something has genuinely reduced the amount of crime and not just the metric, which is worth investigating and hopefully replicating).
In other words, “high crime” and “low crime” do not have the mathematical relationship of A and ~A. Their probabilities do not sum to 1. There is also a third contrasting option, “normal crime”, which is where the “evidence for no mafia” goes.
Seems reasonable to me; if there’s the expected amount of crime in an area, then it’s not too worthy of special attention. If there’s a higher than usual amount of crime, then it’s clearly worthy of special attention.
However, if there’s a lower than usual amount of crime, then it’s also worthy of special attention, because that indicates that something odd is happening there (or, it indicates that something has genuinely reduced the amount of crime and not just the metric, which is worth investigating and hopefully replicating).
In other words, “high crime” and “low crime” do not have the mathematical relationship of A and ~A. Their probabilities do not sum to 1. There is also a third contrasting option, “normal crime”, which is where the “evidence for no mafia” goes.