The research used data from the Federal Probation Sentencing and Supervision Information System, the Federal Bureau of Prisons and the Parole Commission, and a sample of 11,000 defendants convicted during fiscal year 1985. The projections revealed that "straight" probation sentences will be reduced significantly under the guidelines. However, reducing the use of probation will generate only modest demands on the prisons, and then mostly for community corrections phased in over the course of 5 years. The projections also indicate that, while the average time served for violent offenses will increase substantially, the average time served for most property crimes will remain largely the same. Finally, while the forecasts indicate that Federal prison populations will increase significantly by the end of this century, this result is due more to the Anti-Drug Abuse Act of 1986 and the career offender provision of the Comprehensive Crime Control Act of 1984 than to the guidelines themselves. Tables, figures, and footnotes