Giuliani did not get the ball rolling with respect to crime rates, as so many try to claim. Those are merely lies.
I dont think its a lie to say, he instituted Compstat which was directly responsible for the targeting of crime, sharing of tactics, and in general increasing accountability of NYPD policing.
If you are trying to claim that Giuliani was not responsible for huge reductions of crime in NYC, then you are either spewing an utter lie or dont know what you are talking about.