How big a change does this represent? Had African American imprisonment held steady at its highest point (2001 for men, 1999 for women) instead of declining, about 300,000 more African Americans would be in prison right now. Instead they are free to live in the community, to raise families, to hold jobs, to be healthy and happy.

Dramatic failures command attention and therefore often drive efforts at policy reform and innovation. Yet success can be just as informative. It’s just as vital to understand why black imprisonment rates have fallen as it was to understand why they rose. Yet, so far, there is still more discussion about the latter than the former.

It’s time for the debate to catch up with the data. Collapsing crime rates in black neighborhoods surely reduced imprisonment rates, but how did that increase in public safety come about? Did programs to make policing and sentencing more equitable also contribute? Do prisoner reentry programs deserve any credit for reducing incarceration, and if so, which ones? What is being done right that should be expanded to accelerate the positive trends?