Homicide Rates, Down, Up, Why?

I saw this chart (without the blue additions) shared by Michael Hobbes on Bluesky:

I added the blue highlights, which I will discuss below. 

Be sure to note that the data in the chart is per 100,000 people, so the size of the two countries is not a factor. Discussion on Bluesky was both about why the two countries differ so greatly (mostly pointing to gun availability, and some cultural differences), and also about why there was such a big dip in the U.S. rate in the mid-20th century. 

That's where my blue highlights come in. They highlight areas where something happened concerning young men, who are at the prime age to commit homicide, especially in our country with its widely spread tradition of male honor culture.

The reasons that make the most sense to me are that the Great Depression started off with a similar to slightly higher rate, but then it dropped off pretty sharply after the New Deal started (marked with the darker blue line), possibly because a lot of those young men had something better to do because of programs like the CCC and the WPA. 

The downward trend continued in World War II, of course, with conscription and soldiers who volunteered. Right after the war, it went up a bit as they came home, but then dropped again to its lowest level during the 1950s economic boom, with high labor-force participation and unionization rates.

When did it start to go up, eventually to climb to the highest it was in the century?

In 1962, just as the first Baby Boomers were hitting 16 years of age. As each year-cohort of Boomers hit 16, it went up a bit more, until the 1970s when the biggest year-cohorts of the Boom were teenagers (the ones born in the late 1950s — my age group). It started to drop as the Boom eased, and then dropped faster after 1980 for a few years. 

I don't have a great hypothesis for the creep back up to the early 1990s. We all know there was the "crack epidemic" in the mid-1980s, so maybe turf wars related to that, and the economic boom of the Clinton years that started around 1993, which is when the big drop starts on the far right side of the chart. 

Also at that point, Boomers were all in their 30s, and the much smaller Generation X was the right age to be primed for crime, while the more numerous Millennial generation was still too young. I've mentioned before my interest in the leaded gas hypothesis, so maybe that was part of the decrease.

This chart ends in 2000, so what happened after that? The rate in the new millennium did not go up. It declined slowly until 2014, and since then the trend line was up only somewhat...until COVID hit, and then things went awry quickly. Even I would call the increase a spike (almost 29% in a year). The 2022 level is about equal with 1997, so that was some serious backsliding. 

I believe 2023 will see a decrease; it will be interesting to see where it ends up, relative to past years.