Under incapacitation theory, higher incarceration rates are expected to correlate with accelerated reductions in crime. California's contemporary incarceration patterns offer an opportunity to analyze the validity of this theory, particularly as it applies to young people. This study focuses on California's juvenile incarceration and crime trends during the past half century. The findings of this study fail to demonstrate reduced crime rates through higher levels of juvenile incarceration, calling deterrence and incapacitation theories into serious question as effective youth crime reduction strategies and demonstrating the urgent need for California policy makers and legislators to consider alternative theories in response to crime and sentencing. (Contains 27 notes, 3 tables, and 2 figures.)