Although the incarceration rate in the U.S. has leveled off after climbing steadily for three decades, the twenty-first century has seen the emergence of trends which suggest that real criminal justice reform remains elusive, a report from the Vera Institute of Justice finds. Funded by the John D. and Catherine T. MacArthur Foundation, the report, The New Dynamics of Mass Incarceration (44 pages, PDF), found that the prison admission rate nationally has fallen 24 percent since 2006 — due entirely to a 48 percent drop in just ten states — and that the national jail admission rate has fallen 25 percent since 2008. State incarceration rates, however, have fragmented into four different trends — decarceration, stagnation, jurisdictional shifts between prisons and jails, and continued growth. Although thirty-four states are seeing lower overall (prison and jail) incarceration rates, in some states those declines have been driven almost exclusively by larger cities, with smaller cities and towns continuing to see rates rise. And in some jurisdictions, reductions in prison populations have been offset by increases in the jail population or vice versa, while four states continue to incarcerate people in both prisons and jails at record-high rates. To better understand and address the complex dynamics of mass incarceration, the report calls for measuring not just the standard metric of prison population but also jail admissions, pretrial jail populations, sentenced jail populations, and prison admissions.