The report initially describes the structure and operation of OPS and some situational and demographic characteristics of the study data. The study is based on data drawn from 273 excessive-force complaints against police (965 allegations of officer misconduct). The report discusses the results of two multivariate analyses of allegation outcomes that illustrate the importance of evidence in OPS recommendations. The report then explores the role of evidence in determining OPS recommendations. The disposition of 81 percent of the cases was "not sustained." Case characteristics limiting evidence largely contributed to such a result. Nearly half occurred at night; 40 percent had no witnesses other than the victim and the accused; of non-victim witnesses, only 28 percent were independent; negative evidence outweighed positive evidence in 51 percent of the allegations; and negative and positive evidence were equally balanced in 18 percent of the allegations. Fifty-one percent of allegations involving an independent witness were sustained, and 58 percent involving non-testimonial evidence corroborating the allegations were sustained. The OPS typically required testimony from independent witnesses to sustain allegations, so as to ensure to the police constituency that proceedings were fair. 10 tables, 2 references, and 22 notes