IPI scales alone assigned 61 to 77 percent of the officers to the correct performance group (good versus poor), the MMPI scales correctly identified 50 to 70 percent, and the combined scales correctly classified 64 to 87 percent. IPI items measuring difficulties in previous jobs, suspiciousness of others, and anxiety toward the environment were major discriminators between groups. MMPI measures that discriminated between groups included deviation from societal norms and alcohol use. 5 tables and 24 references.