External validity and assignment of experimental vs. control treatment providers within small work groups: a research note

Abstract

Objectives When offenders or victims are randomly assigned to receive experimental vs. current treatments, the external validity of results may depend on whether different treatments are delivered by similar kinds of treatment providers. When treatment providers volunteer to deliver innovative practices in an experiment, it is unclear whether outcomes depend on the content of the treatment, enthusiasm of the providers for the new practice, or both. In such situations, the potential for what we describe as differential predisposition of volunteers for a new treatment raises a question of external validity. Methods We describe the process by which 14 out of 29 mediators across seven Danish police districts came to deliver a new, restorative conferencing method of conducting face-to-face meetings between offenders and their victims, in comparison to longstanding mediation methods. Results We negotiated with all seven District mediation leaders and all 29 of their mediators to use partial random assignment of 14 of the mediators to deliver the new, restorative model. The 14 trained providers of the new method were substantially similar in several measureable characteristics to the 15 other mediators who continued to use the preexisting model, but we cannot measure directly the extent or balance of their predispositions for delivering each model. Conclusions While small work teams pose obstacles to simple random assignment of treatment providers to deliver experimental practices, the random assignment of victims and offenders to two different models of service might be made more externally valid by use of partial random assignment of service providers.

Promoting restorative justice as de jure punishment: a vision for a different future

“…Randomised controlled trials have already been used to test the relative effects of restorative justice and court punishment (see Sherman et al, 2015), and I am currently part of an ongoing Danish trial that tests the relative effects of victim-offender mediation and restorative justice conferences (see Sherman et al, 2021). Surely, there are several challenges in relation to measuring relative effects, including potential selection bias of treatment providers and different predispositions -motivation, willingness, personality, etc.…”

“…-among the service providers who deliver the respective models/interventions. Nevertheless, though such challenges may always remain to some extent, randomised controlled trials are probably the strongest research design to test relative effects, and different strategies may be used to counter the existing challenges of such trials, including full or partial randomisation of service providers (Sherman et al, 2021).…”

Is restorative justice punishment?

“…I have practiced as a mediator in the victim–offender mediation program (“Konfliktråd”) of the Danish national police since 2014. Since 2015, I have been one of two persons responsible for training the program's new mediators (for the Danish program, see Asmussen, 2014, 2015; Hansen, 2012; Henriksen, 2003; Kyvsgaard, 2016; Kyvsgaard & Ribe, 2018; Kyvsgaard, van Mastrigt, & Gade, 2018; Ministry of Justice's Committee on Victim–Offender Mediation, 2008; Rambøll, 2006; Rasmussen, 2020; Sherman, Mastrigt, Gade, Ammann, & Strang, 2020). I am also fortunate enough to have been part of a research team that has observed more than a 100 meetings in the Danish program 2 .…”

“…2 2 These meetings have been conducted in the training and trial phases of the Konfliktråd Impact Project: a randomized controlled trial that our team is currently carrying out in the Danish program in collaboration with the police (see Sherman et al, 2020). This collaboration with the police has provided me with important background knowledge for this article.…”