THE STUDY SAMPLE CONSISTED OF 139 GIRLS FROM THE LAS PALMAS SCHOOL, A RESIDENTIAL TREATMENT CENTER FOR GIRLS. NINETY-FIVE OF THESE GIRLS RESIDED AT THE INSTITUTION AS OF NOVEMBER 30, 1963, AND THE REMAINING GROUP CONSISTED OF GIRLS WHO WERE RELEASED PRIOR TO THIS DATE OR WHO SUBSEQUENTLY WERE PLACED AT THE SCHOOL. THE GIRLS COMPRISED 14 MONTHS OF CONSECUTIVE INTAKE. THEY DISPLAYED A NUMBER OF DISCERNIBLE CHARACTERISTICS REPRESENTATIVE OF THE GENERAL SCHOOL POPULATION OVER TIME. THE SCHOOL STAFF EXPRESSED DISSATISFACTION WITH PSYCHIATRIC DIAGNOSIS AND SUSPECTED THAT TRADITIONAL THERAPEUTIC TECHNIQUES WOULD NOT BE EFFECTIVE FOR MANY OF THE GIRLS. A TYPOLOGY WAS NEEDED THEREFORE THAT COULD BE EMPLOYED REALISTICALLY AND EFFECTIVELY WITHIN THE INSTITUTION. THE INTERPERSONAL MATURITY LEVEL SYSTEM WAS INCORPORATED SUCCESSFULY INTO THE CLASSIFICATION PROCEDURES AT THE INSTITUTION. THE SYSTEM SUGGESTED STAFF STYLES, TREATMENT MODALITIES, AND ETIOLOGICAL ASPECTS OF TYPES OF DELINQUENTS ON THE BASIS OF THE PERCEPTION AND THE BEHAVIOR OF THE GIRLS. AN EFFORT WAS MADE ALSO TO OBJECTIFY THE IDENTIFICATION OF THE INTERPERSONAL MATURITY LEVEL TYPES THROUGH AN ANALYSIS OF THE JESNESS PSYCHOLOGICAL INVENTORY, A 155-ITEM INVENTORY CONCERNING ATTITUDES TOWARD SUCH DIVERSE FACTORS AS FAMILY, POLICE, SCHOOL, AND SELF. THIS ATTEMPT FAILED, ALTHOUGH THE ANALYSIS HELPED UNCOVER COVERT MANIPULATORS EARLY IN THE INSTITUTIONALIZATION PROCESS AND APPEARED TO BE A STEP FORWARD IN THE DEVELOPMENT OF AN OBJECTIVE, GENERAL TYPOLOGICAL SYSTEM. TABULAR DATA ARE INCLUDED. (AUTHOR ABSTRACT MODIFIED--KJM)