NCJ Number
54137
Date Published
1978
Length
79 pages
Annotation
A MODEL IS DEVELOPED FOR PROJECTING GENERAL POPULATION DEMOGRAPHICS (DEMOGRAPHIC-SPECIFIC AND OFFENSE-SPECIFIC ARREST RATES, IMPRISONMENT PROBABILITIES, TIME SERVED, AND THE SIZE AND COMPOSITION OF PRISON POPULATIONS).
Abstract
THE MODEL ACCOUNTS FOR DIFFERENCES IN CRIME RATES AND IMPRISONMENT PROBABILITIES ACROSS DIFFERENT DEMOGRAPHIC GROUPS. IT BEGINS WITH A DEMOGRAPHICALLY DISAGGREGATED PROJECTION OF THE POPULATION IN A JURISDICTION AND PRODUCES PROJECTIONS OF ARRESTS, COURT CASES, COMMITMENTS TO PRISONS, AND PRISON POPULATIONS. THE APPLICATION OF THE MODEL IS ILLUSTRATED BY ESTIMATING DEMOGRAPHIC PROJECTIONS AND MODEL PARAMETERS FOR THE STATE OF PENNSYLVANIA. CHANGES IN THE SIZE AND DEMOGRAPHIC COMPOSITION OF A JURISDICTION'S POPULATION ARE CAUSED BY THREE BASIC FACTORS: BIRTHS, DEATHS, AND MIGRATION. TO MAKE POPULATON PROJECTIONS FOR PENNSYLVANIA, HISTORICAL DATA ON BIRTHS AND DEATHS IN THE STATE WERE OBTAINED THROUGH THE DEPARTMENT OF EDUCATION FOR THE YEARS 1960-1976. THESE DATA, ALONG WITH CENSUS DATA ON THE POPULATION OF PENNSYLVANIA IN 1960 AND 1970, WERE EMPLOYED TO ESTIMATE NET MIGRATION RATES IN RELATION TO AGE, RACE, AND SEX FOR THE PERIOD. ARREST RATES FOR PARTICULAR DEMOGRAPHIC GROUPS WERE DETERMINED BY FOUR FACTORS: (1) PROPORTION OF INDIVIDUALS IN A GROUP WHO COMMIT CRIME, (2) FREQUENCY WITH WHICH THOSE INDIVIDUALS COMMIT CRIME, (3) TYPES OF CRIME COMMITTED, AND (4) LIKELIHOOD THAT THE POLICE ARREST SOMEONE IN A GROUP (FALSELY OR PROPERLY) IN RESPONSE TO A PARTICULAR CRIME. THE PROCESSING OF ARRESTEES BY THE JUDICIAL SYSTEM WAS REPRESENTED BY THREE SEPARATE PARAMETERS: (1) PROBABILITY OF AN ARREST RESULTING IN A CRIMINAL COURT CASE BEING FILED, (2) PROBABILITY OF A CRIMINAL COURT CASE RESULTING IN A CONVICTION, AND (3) PROBABILITY OF A CONVICTED OFFENDER BEING SENTENCED TO PRISON. THE TIME AN INMATE SPENT IN PRISON WAS EVALUATED IN RELATION TO THE SENTENCE LENGTH IMPOSED BY THE COMMITTING COURT AND DECISIONS OF THE PAROLE BOARD ABOUT THE TIME OF RELEASE. ARREST RATES AND IMPRISONMENT PROBABILITIES VARIED CONSIDERABLY ACROSS DEMOGRAPHIC GROUPS IN PENNSYLVANIA. IT IS PROJECTED THAT SIGNIFICANT CHANGES WILL OCCUR IN THE DEMOGRAPHIC COMPOSITION OF THE GENERAL POPULATION IN THE FUTURE. THE MODEL CAN SERVE AS AN IMPORTANT TOOL IN POLICY ANALYSIS FOR THE CRIMINAL JUSTICE SYSTEM. SUPPORTING DATA AND MATHEMATICAL EQUATIONS ASSOCIATED WITH THE MODEL'S APPLICATION IN PENNSYLVANIA ARE PROVIDED. NOTES ARE INCLUDED, AND APPENDIXES CONTAIN THE ARREST RATE ESTIMATION METHODOLOGY AND THE POPULATION PROJECTION METHODOLOGY. (DEP)