Rounds per shooting
The number of rounds fired went up at NYPD after the switch to autoloaders.
This could mean that the police, with more ammo available, went to a spray'n'pray mode, which would have been avoided had they stuck with revolvers.
To some extent, it very well may mean that.
However, there are other pieces to the puzzle.
For instance, police departments started switching to autos in the 80's; the Connecticut State Police prominently chose the Beretta 92, right after the military adopted the M9. Others followed, through the late 80's and early 90's.
However, at around this time, it seems to me that the military in particular, and police departments in general, started reducing actual hands-on training time with weapons; lengthening the time periods between recurrent training; and reducing the standards required for initial and recurrent qualification.
This could also result in a much higher number of rounds fired per police incident.
Add to that the increased number of drug related violent incidents. BG's have been better armed, and more willing to open fire. This would tend to result in more officer movement (taking cover, ducking, etc), and therefore a higher miss rate, the more the BG's shot back.
So it's hard to say, based on number of shots fired, whether autoloader vs revolver makes that much difference, compared to lower training standards and more violent BG's.