As a man accustomed to scanning spreadsheets full of discouraging numbers — about rising costs and diminishing revenues — Governor Dannel P. Malloy was uncharacteristically buoyed this week by a statistical report by the FBI that included some encouraging numbers about crime rates in Connecticut. Violent crime in the state has dropped by nearly 10 percent for the second year in a row with 236.9 violent crimes per 100,000 persons in 2014, lower than the aggregated rates in New England (287.2), the Northeast (322.5), and the United States as a whole (357.7). Nationally, the number violent crimes declined by one-tenth of one percent; in Connecticut, the rate dropped 9.7 percent.

This was truly good news. For a governor desperate for silver linings on a list of talking points about a state with a sluggish economy and looming budget deficits, the temptation was great for him to link the good news to some of his own policy initiatives. He did not resist. Flanked by law enforcement officials on Monday, he suggested that state programs to address homelessness and how juveniles are handled by the criminal justice system had had an impact. Maybe so. But finding motives for crimes not committed seems to lend itself more to speculation than to serious analysis — though not always.

Earlier this year, the Brennan Center for Justice at the NYU School of Law issued a report called What Caused The Crime Decline? It reviewed data compiled over 40 years from all 50 states and the 50 largest cities. The report looked at social, economic, and environmental factors, including the aging of the famous demographic bulge of the baby boomers. (Most crimes are committed by people between the ages of 15 and 34.)

The report assessed a period in which tough-on-crime policies dramatically increased incarceration, which has now reached a point where nearly 1 in 100 Americans is behind bars — a rate unmatched anywhere in the world. When 1 in 28 children has a parent in prison, entrenched poverty and missed opportunities consign certain precincts of our society to a criminal justice system that metes out de facto collateral punishments to innocents.

Mass incarceration, the Brennan Center study found, has had no effect on crime rates since 2000 and has little or nothing to do with declining rates of violent crime. It notes that a year in prison can cost more than a year at Harvard. The United States spends $260 billion each year on criminal justice. And thankfully, not all of that goes toward locking people up. The advent of data-driven community policing techniques, along with expanded treatment and rehabilitation programs, are having an impact in communities struggling with violent crime.

So we will not deny the Gov Malloy his moment of pride and satisfaction over the good news about crime in Connecticut. We will even acknowledge that his “Second Chance Society” legislation signed into law this summer designed to reintegrate nonviolent offenders into their communities is likely to yield more public safety dividends than putting more and more people behind bars. As the governor said in signing that law, “We can truly be tough on crime by being smart on crime.”