One of the questions concerning organized crime is in terms of street crime and random violence, is it is better to have a couple of organized criminal groups that follow certain rules then a thousand street gangs that answer to no one. In the case of New York and their problems with organized crime, has anyone compared the levels of violence and street crime from the height of the power of the Five Families from 1940-1960 to 2016?
I think you may have trouble getting a solid answer to this question, because you're making a couple of suppositions that are very hard for historians to deal with.
First, that there was any such thing as organised crime groups that not only consistently followed set "rules", but also had the power to control the level of street violence in a large city, or even small parts of a large city – this is very much a "movie" image of the Mafia which bears little resemblance to reality.
Second, that even if the actions of organised crime had any impact on street crime and random violence, that it's possible to distinguish between that effect and the myriad other changes in social, economic, environmental and policing factors that will also have an impact on relative rates of street crime over a period of decades.
You might have more luck if you tried rephrasing your enquiry more along the lines of "Has organised crime had any measurable impact on the incidence of other types of crime in New York since 1940?"