INMATES IN THE FEDERAL CORRECTIONAL INSTITUTION AT TALLAHASSEE, FLA., WERE CLASSIFIED BY STAFF INTO THREE GENERAL CATEGORIES: (1) THOSE MOST LIKELY TO ACT OUT AGGRESSIVELY, (2) THOSE LIKELY TO BE VICTIMS, AND (3) THOSE IN NEITHER OF THE FIRST TWO EXTREME GROUPS. INMATES WERE ALSO RATED ACCORDING TO THEIR PERFORMANCE ON THE MINNESOTA MULTIPHASIC PERSONALITY INVENTORY (MMPI), A COLLECTION OF 566 TRUE-FALSE STATEMENTS WHOSE RESPONSES ARE USED AS A PERSONALITY MEASURE. OVERALL, CLASSIFICATION WAS BASED ON MMPI GROUPS, BEHAVIOR RATINGS ON THE CORRECTIONAL ADJUSTMENT CHECK LIST, AND A REVIEW OF RECORDS. AFTER THE INITIAL POPULATION WAS CLASSIFIED, A CENTRAL ADMISSION AND ORIENTATION UNIT FOR THE IDENTIFICATION AND CLASSIFICATION OF INCOMING INMATES WAS ESTABLISHED, AND THE EXISTING POPULATION WAS REARRANGED INTO UNITS WHICH REFLECTED THE CLASSIFICATION. INMATES WERE ASSIGNED TO ONE OF THREE OPEN DORMITORIES, WITH THE TWO EXTREME GROUPS SEPARATED FROM EACH OTHER. ALL INMATES COULD LATER APPLY FOR A FOURTH UNIT FEATURING MORE INTENSIVE PROGRAMS. IN THE MAKING OF FINAL ASSIGNMENTS, THE MMPI TYPES PROVED HELPFUL AS A STARTING POINT FOR THE CLASSIFICATION, BUT CONSIDERATION OF OTHER INFORMATION WAS NECESSARY. A DATA RETRIEVAL SYSTEM WAS DEVELOPED TO EVALUATE THE CLASSIFICATION SYSTEM AND ITS EFFECTS ON THE INSTITUTION. RESULTS COMPARING 9 MONTHS BEFORE INTRODUCTION OF THE SYSTEM WITH 9 MONTHS AFTERWARD SHOWED NO DIFFERENCES IN THE NUMBER OF MEN SENT TO THE MAXIMUM SECURITY SECTION OR IN THE NUMBER OF WRITTEN REPORTS OF INSTITUTION RULE INFRACTIONS. HOWEVER, SERIOUS INCIDENTS DECREASED (315 VERSUS 289) AS DID ASSAULTS (24 VERSUS 13). THESE AND OTHER RESULTS SUGGEST THAT THE SYSTEM HAS CONTRIBUTED TO MAKING THE INSTITUTION SAFER AND HAS FACILITATED MANAGEMENT DECISION. THE DATA RETRIEVAL SYSTEM IS DETAILED. TABULAR DATA REFERENCES, AND FOOTNOTES ARE PROVIDED, AS WELL AS A LIST OF PREVIOUS PUBLICATIONS OF THE FEDERAL CORRECTIONAL INSTITUTION'S RESEARCH REPORTS. (AUTHOR ABSTRACT MODIFIED--WJR)