In some circles the social sciences are criticized for “discovering” what common sense supposedly already tells us. But sometimes, societal trends can cause even the experts to scratch their heads. During the recent recession, for example, unemployment rates in the United States rose sharply and many scholars and politicians expected crime rates to follow suit. According to recently released FBI crime statistics, though, they haven’t.

Violent crimes have fallen 6.4 percent in the last year while property crimes dropped 3.7 percent. Plus, last year’s crime decrease was just a continuation of a downward pattern since 2008; since 1991, the homicide rate has fallen 51 percent and property crimes dropped by 64 percent.

When this data went public, news sources like National Public Radio, the LA Times, and MSNBC.com looked to see how experts in criminology reacted to the findings. Richard Rosenfeld, professor at the University of Missouri-St. Louis and former president of the American Society of Criminology, was, “surprised by the overall decline in both violent and property crime during and since the recent recession.” He went on, “I’ve studied crime trends in relation to economic conditions for some time, and the 2008-09 recession is the first time since WWII that crime rates have not risen during a substantial downturn in the economy.” Many, including Rosenfeld, attribute some of the decline to smarter policing, but admit that can’t account for all of it, since in many places policing hasn’t changed much in the past ten years or during the recession.

Franklin Zimring, a criminologist and UC Berkeley law professor, was also a puzzled to see a decline in crime during the last three years when incarceration rates have stalled and the economy has soured. “By both the left- and right-wing leading indicators we should be in a lot of trouble—except [we’re] not,” Zimring maintains. “Everything we thought we knew are deeply challenged by events by the last three years.” In an email written to msnbc.com, Zimring does, though, suggest one possible factor affecting this decline: Inflation. “High rates of inflation are connected with high crime rates, so when inflation drops we should expect corresponding declines in crime, in the first instance property crime.”

Although bewilderment in the face of a crime decline is a relatively good problem to have, most scholars and public officials still agree on the importance of getting to the bottom of what’s causing it—particularly if it might be replicable.