So what role did these variables play?
"... over-harsh criminal justice policies, particularly increased incarceration, which rose even more dramatically over the same period, were not the main drivers of the crime decline.
More important were various social, economic, and environmental factors, such as growth in income and an aging population. The introduction of CompStat, a data-driven policing technique, also played a significant role in reducing crime in cities that introduced it."
Crime declined dramatically nationwide over the past two decades. We reviewed more than 40 years of data from all 50 states and the 50 largest cities to determine why.
www.brennancenter.org
So does this all mean that we should not be looking at any other variable now to try to reduce the crime rates further?