Why the Crime Drop?

The “crime drop” is the most important criminological phenomenon of modern times. In North America, Europe, and Australasia, many common crimes have fallen by half or more since the early 1990s, albeit with variation in the specifics. Seventeen explanations are examined here including demographics, policing, imprisonment, drug markets, and lead poisoning. Pioneering research relevant only to the United States now appears, with the benefit of hindsight, somewhat parochial. Sixteen of the 17 hypotheses fail one or more of four evidence-based standardized tests on which they are assessed. The one that passes is the security hypothesis, underpinned by crime opportunity theories. Here there is strong evidence that vehicle theft fell because of more and better security, and mounting evidence that improved security was critical in reducing burglary and other acquisitive crime. Many crime types are interrelated, while most criminal careers are dominated by property crime, so removing these volume crimes might be expected to reduce violence.