Systematic Reviews and Meta-Analyses: Best Evidence on “What Works” for Criminal Justice Decision Makers

With the current emphasis on making “evidence-based policy,” criminal justice policymakers today are under more pressure to use research in their decision making. Systematic reviews and meta-analyses can provide policymakers with reliable and comprehensive evidence about what works to reduce crime or improve justice. It is important that decision makers become more familiar with this method. In this article, we present a non-technical summary of systematic reviews. After discussing the need for different evidence to respond to different questions, we examine some of the challenges in locating “evidence.” A common method for reviewing literature—the narrative or traditional synthesis—contains a number of methodological flaws that have contributed to the current emphasis on rigorous or systematic reviewing techniques. We consider two policy-relevant examples of systematic reviews addressing popular justice programs (Scared Straight and D.A.R.E.) and conclude with the argument that systematic reviews and meta-analyses offer the most useful information to decision makers who want to base their decisions on “what works” rather than ideology, tradition, politics, or anecdote.