America’s incarceration rate is in decline

>Rapidly declining numbers of youth are committing crimes, getting arrested, and being incarcerated. This matters because young offenders are the raw material that feeds the prison system: As one generation ages out, another takes its place on the same horrid journey.

Another factor which will soon impact this, if it isn't already, is the rapidly changing nature of youth. Fertility rates have been dropping since 2009 or so. Average age of parents is increasing. Teen pregnancy on a long and rapid decline.

All of these working together means that each year the act of having a child is much more deliberate and the parents likely having more resources. Which in turn should mean fewer youth delinquency, which as the article notes is how most in prison started out.

But it's not uniform. In the span of ~60 years, the average birth rate doesn't matter as much as the distribution and how much the children model their parents.

Small example (multiply all numbers by 1M), average birth rate of 1.5 can be a group of 4 people where one had 0 children, one had 1, one had 2, one had 3. If each child has as many children as its parents, next generation, 0 have 0 children, 1 has 1, 2 have 2, 3 have 3, for a new average of 2.33.

If you take a higher starting average but a tight spread [2, 2, 2, 2], the next average is only 2. Or if you have [0, 1, 2, 3] but kids model society instead of parents, you get 1.5 again.

Of course children didn't model their parents the past couple of generations, but times may be changing.