A NATIONAL SURVEY WAS CONDUCTED OF ALL FEDERAL AND STATE CORRECTIONAL INSTITUTIONS, AN ASSESSMENT WAS MADE OF FORECASTING TECHNOLOGY AND PRELIMINARY APPLICATION OF FOUR PROJECTION TECHNIQUES, AND CASE STUDIES WERE UNDERTAKEN TO ILLUMINATE THE MECHANISMS DETERMINING PRISON POPULATION POLICY BY STATE GOVERNMENTS. IMPORTANT DIFFERENCES REGARDING THE PRISON CROWDING PROBLEM IN FOUR STATES ARE DISCUSSED. DATA OF THE NATIONAL SURVEY OF STATE AND FEDERAL CORRECTIONS AGENCIES AND INSTITUTIONS ARE ANALYZED WITH PARTICULAR REFERENCE TO THE ISSUES OF CAPACITY AND ADEQUACY OF FEDERAL AND STATE PRISONS. THE RATIONALE FOR THE PARTICULAR METHODS USED IN THE STUDY IS PRESENTED, AND THE UNDERLYING ASSUMPTIONS AND LIMITATIONS OF THESE METHODS ARE OUTLINED. THE RELATIONSHIP BETWEEN POLICY AND PROJECTIONS IS EXPLORED. RESULTS FROM THE TWO TREND ANALYSIS TECHNIQUES UTILIZED DURING PHASE I ARE PRESENTED. THESE POLICY-BLIND METHODS ASSUME, RESPECTIVELY, THAT INTAKE AND RELEASE RATES CONTINUE AT THEIR PRESENT LEVELS, PRODUCING CONSTANT GROWTH IN THE INMATE POPULATION; AND THAT SENTENCE LENGTH AND ADMISSIONS TO PRISON PERSIST AT THEIR PRESENT LEVELS CAUSING POPULATIONS TO CEASE GROWING AFTER 2 YEARS. THE SCOPE AND LIMITATIONS OF THE DYNAMIC MODELING TECHNIQUE WHICH ATTEMPTS TO ACCOUNT FOR THE DIFFERENTIAL IMPACT OF SPECIFIC POLICY ALTERNATIVES IS REVIEWED. THE POLICY SCENARIOS ARE DESCRIBED IN SOME DETAIL, ALONG WITH THE RESULTS OF THE MODELING EXERCISE THAT WAS APPLIED TO FIVE STATES AND TO THE FEDERAL PRISON SYSTEM. THE EXPLORATORY NATURE OF THIS EXERCISE IS EMPHASIZED. FINALLY, A NUMBER OF KEY POLICY ISSUES ARISING FROM THE STUDY WHICH CONFRONT FEDERAL AND STATE GOVERNMENTS ARE OUTLINED. A BIBLIOGRAPHY IS INCLUDED. FOR VOLUME II SEE NCJ - 44357.