IT IS CONCLUDED THAT EMPIRICAL RESEARCH DOES NOT EXIST EITHER TO VALIDATE OR INVALIDATE CATEGORICALLY THE DIVERSION CONCEPT. HOWEVER, THE STUDIES REVIEWED HAVE AN IMPACT ON THE CONTROVERSY OVER WHETHER DIVERSION HAS AN IMPACT ON CLIENT OUTCOME OR ON THE CRIMINAL JUSTICE SYSTEM. A BRIEF DISCUSSION OF THE DESCRIPTIVE STUDIES OF DIVERSION PROVIDES A BACKGROUND FOR UNDERSTANDING THE DIVERSION CONCEPT. A SHORT DESCRIPTION OF THE METHODOLOGICAL QUESTION OF RESEARCH DESIGN, IMPORTANT IN DETERMINING THE VALIDITY OF DIVERSION STUDIES, IS PRESENTED. TWO REVIEWS ARE DESCRIBED WHICH ASSESS DIVERSION STUDIES COMPLETED BEFORE 1974; THEY FOUND THAT METHODOLOGICAL PROBLEMS LIMITED THE VALIDITY OF THE STUDIES' RESULTS. STUDIES OF RELATED AREAS IN CRIMINAL JUSTICE ARE DESCRIBED TO PROVIDE A COMPARISON OF RESEARCH QUALITY IN THESE STUDIES AND IN DIVERSION. RESEARCH FINDINGS IN PRETRIAL DIVERSION PUBLISHED SINCE 1974 AND THROUGH 1977 ARE REVIEWED. THREE TYPES OF STUDIES ARE INCLUDED: (1) TWO WHICH EMPLOY APPROPRIATE RESEARCH METHODOLOGY -- ONE OF THESE USES AN EXPERIMENTAL DESIGN, THE OTHER A SYSTEMATICALLY DEVELOPED QUASI-EXPERIMENTAL DESIGN; (2) TWO WHICH USE SUCH FLAWED METHODOLOGY THAT THE RESULTS ARE QUESTIONED; AND (3) SEVERAL SPECIALIZED RESEARCH STUDIES WHICH EXAMINE VARIOUS ASPECTS OF DIVERSION PROGRAMS SUCH AS SOCIAL CONTROL, WOMEN AND DIVERSION, AND THE IMPACT OF INTERNAL PROGRAM PRACTICES ON CLIENT OUTCOMES. ALL OF THE STUDIES REVIEWED DEAL EXCLUSIVELY WITH 'CLASSICAL' ADULT DIVERSION PROGRAMS, I.E., THOSE WHICH DEAL WITH ADULT DEFENDANTS; OFFER AN ALTERNATIVE TO TRADITIONAL CRIMINAL JUSTICE PROCESSING; ARE VOLUNTARY; OCCUR PRIOR TO ADJUDICATION, AFTER ARREST, AND AFTER PROSECUTORIAL SCREENING; OFFER SERVICES TO THE CLIENT; AND RESULT IN DISMISSAL OF CHARGES FOR COMPLETION OF THE PROGRAM.