Yet a little-noticed migration trend may reduce crime in the next decade: a significant movement of African-Americans out of big cities. If this trend continues, it could portend reductions in crime. Low-income blacks, especially young males, commit a disproportionate amount of the violent crime in this country. That’s why their migration in the ’60s raised crime rates in cities. A recent analysis of census data by Politico found that from 2010 to 2020 nine of the 10 cities with the highest proportions of blacks (Houston was the exception) were losing minority population. Some declines were dramatic: Detroit lost more than 277,000 of its African-American residents, Chicago more than 261,000 and New York in excess of 176,000. Unless immigration and migration patterns change in coming decades, this factor is unlikely to support a new crime tsunami.

A second consideration is age distribution. The American population is aging, and the once-violent baby boomers have mellowed considerably. In 2021 more than 21% of Americans were baby boomers and the 65-plus age group is projected to constitute more than a fifth of the population through 2060. Meanwhile, men 18 to 24 are a declining proportion of Americans. In 2020 they were an estimated 4.7% of the U.S. Their proportion is projected to decline to 4.5% in 2025 and 4.4% in 2030. Though these declines aren’t dramatic, the downward trajectory augurs well for violent crime forecasts.

The final consideration is the strength of the criminal-justice system.