The theory: the economy got better and crime got less appealing

The case for: When people don’t have jobs or aren’t making money, crime might look like a profitable alternative. Research has shown that increases in unemployment, for example, lead to small increases in property crime. And some criminologists are enthusiastic about the correlation between inflation and rising crime levels.

The case against: The big problem with this argument: the recession of the late 2000s. Unemployment was higher in 2009 and 2010 than it was in the crime-wave 1980s and early 1990s. But crime didn’t spike — instead, surprising many, it continued to decline.

The bottom line: Still unclear. It depends on what measure of economic well-being we’re talking about. The Brennan Center, reviewing past research on the subject, found in February 2015 that rising income slightly reduced crime since the 1990s, and unemployment also played a role, albeit a smaller one. Reduced inflation, meanwhile, might have had a slight effect on property crime — but it probably didn’t affect violent crime.

One interesting question: How much does it matter that the economy is actually improving, as opposed to people simply feeling that the economy is improving? There’s some suggestive evidence that rising “consumer confidence” (a statistic based on surveying people about the economy) brought crime down not only in the 1990s, but in the 2000s as well.