The study found that States with a combination of determinate sentencing (abolition of discretionary parole release) and presumptive sentencing guidelines had lower incarceration rates and a smaller growth in these rates than other States. These policies had to be implemented in combination in order to have this effect. States with separate time-served requirements for violent offenders had higher incarceration rates than States without such requirements, and States with a higher number of sentencing extensions for drug offenses had comparatively higher incarceration rates. Also, States with a higher number of mandatory sentencing laws had higher incarceration rates; however, no link was found between laws that increased prison sentences for second-time or third-time offenders and the incarceration rate. Factors other than law and policy that increased incarceration rates were higher property-crime rates, larger minority populations, a higher unemployment rate, more revenue per capita, a higher number of arrests for drug offenses, a Republican governor, a higher number of religiously conservative residents, and a higher number of politically conservative residents. States with higher income per capita and more generous welfare benefits had lower incarceration rates. Using a pooled time-series cross-sectional design and using data for all 50 States obtained from several government sources, the study isolated the influence of sentencing and corrections policies on changes in State incarceration rates between 1975 and 2002. The analysis controlled for a number of demographic, economic, ideological, and crime-related variables. Extensive tables, 140 references, and 5 appendixes with supplementary descriptions of data collection and analysis