Corrections_Today_September_October_2020_Vol.82_No.5

nEWS & vIEWS

NIJ Update

Randomized controlled trials in correctional settings By Kristofer Bret Bucklen, Ph.D.

P rogram evaluation is essen- tial to ensuring that prison systems adopt effective programs and policies. The “gold standard” method for evaluating outcomes of programs and policies is the randomized controlled trial (RCT), a type of scientific experi- ment featuring random assignment of individuals to either a treatment or control group in order to precisely measure the treatment’s impact. This article presents an overview of the RCT design, as well as its use and importance in a correctional setting. The takeaway from this article is that, while conducting RCT evaluations can be met with skepti- cism and challenges, where feasible RCTs deliver superior, more reliable evaluations of the impact of policies and programs. Causal inference A singular advantage of RCTs, over other evaluation methods, is their ability to reliably establish a causal link between a program or policy and an outcome. When evaluating the impact of a particular program or policy, an evaluator is typically attempting to

Photo illustration: Jail cell: istock/Rawf8; gold medal: istock/BrianAJackson

draw that link between the program or policy (X) and a specific outcome (Y), independent of any other external influences (Z). This is referred to as causal inference. In order to develop a strong causal link between program or policy X and outcome Y, at least three criteria must be satisfied:

1. X must precede Y temporally; 2. X and Y must “covary” together — that is, whenever X changes, Y changes in correlation to X; and 3. There can be no other factor Z that explains the relationship between X and Y.

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