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Base Expectancy Model for Forensic Release Decisions

NCJ Number
M Cohen; J T McEwen; K Williams; S B Silver; M K Spodak
Date Published
206 pages
The National Institute of Justice instituted the Classification, Prediction, Methodology Development Research Program in response to the growing need to deal with offender classification issues and criminal behavior prediction, and a Base Expectancy Model for Forensic Release Decisions Project was undertaken as part of this program in 1984.
The project was initiated in cooperation with Clifton T. Perkins Hospital Center (CTPHC), a maximum-security facility for the evaluation and treatment of mentally ill offenders in Jessup, Maryland. Project objectives were to assess and compare differences in background, characteristics, and treatment for a group of insanity acquittees, prisoners transferred to the mental hospital for treatment, and control prisoners without identified mental illnesses; to assess offender recidivism and outcome over a 5-year followup period; and to assist CTPHC clinical staff in making release decisions through the development of actuarial prediction tables of patient release readiness and favorable outcome. The project focused on 135 men found not guilty by reason of insanity (NGRI) who were released from the CTPHC between 1967 and 1978. Data were collected from CTPHC case records, parole and probation case records, arrest histories from the Federal Bureau of Investigation (FBI) or the Maryland State Police, and rehospitalization records. Results indicated that, during the 5 years after release, 54.3 percent of NGRI patients, 73.3 percent of prison transfers, and 65.4 percent of controls were rearrested. All three groups showed a decrease in normalized arrest rates before versus after hospitalization. The actual percentage change in the number of arrests before and after was 13 percent in NGRI and prison transfer groups and 9.5 percent in the control group. Prison transfers had not only more frequent rearrests but also the worst outcomes after release on nearly all outcome variables. Prison transfers also had poorer levels of functioning prior to the instant offense, higher prior arrest rates, and the same amount of prior mental hospitalizations as the NGRI group. In addition, prison transfers were more psychotic at the time of admission to the mental hospital and received considerably less and shorter treatment than NGRI patients. The authors discuss the background and characteristics of NGRI's, prison transfers, and controls; describe the course of hospital treatment; and examine in some detail variables affecting outcome after release. They also address methods for predicting outcome that are based primarily on overall functioning and recidivism. Appendixes include an outcome predictor inventory, salient factor scores, occupation codes, and FBI index crimes. 91 references and 49 exhibits