Developing a process evaluation model in the GASP (groups for alcohol-misusing short-term prisoners) trial

Conducting a process evaluation of a complex intervention allows researchers to examine mechanisms of change not captured elsewhere. The MRC has published guidance[1] to support development of a streamlined approach and for reporting across public health interventions generally. Given the complex nature of the prison environment and in particular the many contextual factors that can impact on intervention delivery, a process evaluation is essential in a trial conducted in this setting. However, little guidance exists on the tailoring of process evaluations for complex environments where contextual factors may have a particularly significant impact. In this paper we present a process evaluation model for the Groups for Alcohol-misusing Short-term Prisoners (GASP) trial, following MRC guidance.