Experts see a combination of factors behind the nation’s crime decline. Here are some of the most common theories:
- Better policing. Law enforcement strategies have improved over the past two decades, and police have better access to data that can help identify where and when crimes occur.*
- Waning crack cocaine demand. Violence and addiction that characterized the crack epidemic of the 1980s have subsided.†
- Changing demographics. The average age of the U.S. population has risen, and research shows that older people commit fewer crimes.‡
- More incarceration. The U.S. prison population has increased dramatically since the early 1990s, taking many dangerous offenders off the streets.§
- The economy. Generally favorable economic trends through the 1990s and into the 2000s reduced unemployment and some of the impetus for crime.||
- Less cash. Certain street crimes may be less common because Americans tend to carry less cash than in the past due to the growth of digital transactions.#
- Technology. Anti-crime technology, ranging from sophisticated car- and home-alarm systems to video surveillance equipment, has become widespread.**
- Private security. A significant rise in the number of private security personnel has served as an additional deterrent.††
- Lead exposure. Americans’ exposure to lead—which has been linked to aggressive behavior in children and associated with future crime—has declined.‡‡
* Jeremy Travis and Michelle Waul, Reflections on the Crime Decline: Lessons for the Future? (Washington: Urban Institute, August 2002), http://www.urban.org/uploadedpdf/410546_crimedecline.pdf.
† Alfred Blumstein and Joel Wallman, The Crime Drop in America (New York: Cambridge University Press, 2005).
‡ Alfred Blumstein and Richard Rosenfeld, “Factors Contributing to U.S. Crime Trends,” in Understanding Crime Trends: Workshop Report, eds. Arthur S. Goldberger and Richard Rosenfeld (Washington: National Academies Press, 2008), 13, http://www.nap.edu/openbook.php?record_id=12472&page=13.
§ Jeremy Travis, Bruce Western, and Steve Redburn, eds., The Growth of Incarceration in the United States: Exploring Causes and Consequences (Washington: National Academies Press, 2014).
|| Franklin E. Zimring, The Great American Crime Decline (New York: Oxford University Press, November 2006).
# Richard Wright et al., “Less Cash, Less Crime: Evidence From the Electronic Benefit Transfer Program,” National Bureau of Economic Research Working Paper Series (2014), doi: 10.3386/w19996.
** Graham Farrell et al., “The Crime Drop and the Security Hypothesis,” Journal of Research in Crime and Delinquency 48, no. 2 (2011): 147, doi: 10.1177/0022427810391539.
†† Philip J. Cook and John MacDonald, “Public Safety Through Private Action: An Economic Assessment of BIDs, Locks, and Citizen Cooperation,” Economic Journal 121 (2010): 445, http://www.nber.org/papers/w15877.pdf.
‡‡ Jessica Wolpaw Reyes, Environmental Policy as Social Policy? The Impact of Childhood Lead Exposure on Crime, National Bureau of Economic Research Working Paper Series (2007), http://www.nber.org/papers/w15877.pdf.