Statistical Power and Criminal Justice Research

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This comprehensive power-analytic investigation reviewed 129 articles in eight leading criminal justice/criminology journals. Three statistical power determinations were made for each of 3689 reported tests of significance, and the average power for detecting a range of possible treatment effects was calculated for each of the fifty-three studies subsequently included in the analysis. Among other findings, fully sixty-six percent of the fifty-three articles analyzed had less than a 50-50 chance of detecting a "small" treatment effect. Average power figures culled from similar surveys in other disciplines demonstrated that the problem of low statistical power is not unique to research in criminal justice/criminology. In fact, this survey found appreciably higher power levels than have been revealed in other disciplines. Additionally, the practical consequences of low statistical power are outlined, and workable guidelines for reporting the information necessary for the independent evaluation of published studies are provided.