The rate of juvenile incarceration in California showed an 80-percent decline between 1980 and 2010. As of 2010, only 33 in every 100,000 California youth ages 10-17 were confined in State correctional facilities. This is the lowest recorded youth commitment rate in California history. Despite the declines in youth incarceration in California, the juvenile violent crime rate declined by 39 percent, and the juvenile felony rate declined by 60 percent during the period 1980 through 2009. Currently, a California teenager is less likely to be arrested for a felony than a teenager in 1955. During this same period, California's per-capita adult imprisonment rate increased four-fold. The adult violent crime rates remained virtually the same. The period of greatest imprisonment increases for both juveniles and adults, 1980-1995, coincided with generally increased violent crime; and the period of greatest declines in imprisonment (1995-2009), coincided with large declines in violent crime for all ages. These findings challenge the prevailing "incapacitation" assumption that more imprisonment leads to less crime due to fewer offenders remaining in the community to commit more crimes. 5 tables