A systematic review of 40 religiosity and juvenile delinquency studies conducted by Johnson and colleagues (2000a) concludes that many studies do not explore the role of religiosity in explaining and understanding delinquency. The authors posit that the ways in which religiosity is measured may explain some of the inconsistent findings in research. For example, studies that use multiple indicators to measure religiosity and studies that make a decision to use religiosity measures based on their reliability tests tend to find that religion consistently has a deterrent effect on delinquency. In contrast, studies that do not use multiple indicators of religiosity and do not administer reliability tests for multi-item measures of religiosity typically find inconsistent effects for the deterrent role of religion on delinquency. Overall, this review concludes that religion has a negative association with delinquency, and with improvement in measurement as well as analytic methods, there should be more consistent empirical results that support this perspective.
Baier and Wright (2001) systematically review the findings of 60 studies about the effect of religion on crime. This review provides additional possibilities for understanding why inconsistent findings exist. The authors assert that (1) studies using religiously based samples tend to produce significantly stronger deterrent effects for religion, (2) studies examining nonviolent crime tend to show stronger deterrent effects, and (3) studies using small sample sizes and more racially diverse samples tend to show stronger deterrent effects. This meta-analysis finds evidence for a moderately strong deterrent effect of religion on crime. Similar to Johnson and colleagues review, this study concludes that a better understanding of the impact of research methodologies on outcomes will increase the quality and consistency of future research in this area.