THE REVIEW ENCOMPASSES THE FOLLOWING STUDIES: (1) A 1959 COMPARISON OF HOMICIDE RATES IN CONTIGUOUS STATES WITH AND WITHOUT CAPITAL PUNISHMENT LAWS, WHICH FOUND NO EVIDENCE OF A DETERRENT; (2) THE CONTROVERSIAL TIME-SERIES STUDY OF ISAAC EHRLICH, WHOSE REGRESSION ANALYSES OF NATIONAL DATA LED HIM TO CONCLUDE THAT EXECUTIONS ARE A DETERRENT TO MURDER; (3) ASSESSMENTS OF EHRLICH'S WORK; AND (4) STUDIES THAT APPLIED ECONOMETRIC TECHNIQUES TO CROSS-SECTIONAL (CROSS-STATE) DATA AND FOUND NO SUPPORT FOR THE DETERRENCE HYPOTHESIS. METHODOLOGICAL ISSUES RAISED BY THESE STUDIES, PARTICULARLY BY THE EHRLICH ANALYSIS, ARE DISCUSSED AT LENGTH. IT IS CONCLUDED THAT, WHILE THE STUDIES MAY PROVE USEFUL IN POLICY DECISIONMAKING ON SUCH MATTERS AS POLICE BUDGET ALLOCATIONS AND PERSONNEL DEPLOYMENT, THEIR APPLICATION IN DECISIONS TO PERMIT OR NOT TO PERMIT CAPITAL PUNISHMENT IS NOT WARRANTED. SPECIFIC REASONS FOR NOT USING EHRLICH'S RESULTS TO PASS JUDGMENT ON THE DEATH PENALTY ARE ENUMERATED. THE NEED TO PURSUE DETERRENCE RESEARCH SO THAT EVENTUALLY IT CAN CONTRIBUTE TO IMPORTANT LEGAL POLICY DECISIONS IS NOTED. IT IS POINTED OUT THAT, TO DATE, THE STRONGEST CONCLUSION THAT CAN BE REACHED ABOUT THE DETERRENT EFFECT OF CAPITAL PUNISHMENT IS THAT IT IS NOT SETTLED QUESTION. (LKM)