The effectiveness and cost-effectiveness of a group domestic abuse perpetrator programme: protocol for a randomised controlled trial

BACKGROUND: In contrast to evidence for interventions supporting victim/survivors of domestic violence and abuse (DVA), the effectiveness of perpetrator programmes for reduction of abuse is uncertain. This study aims to estimate the effectiveness and cost-effectiveness of a perpetrator programme for men. METHODS: Pragmatic two-group individually randomised controlled trial (RCT) with embedded process and economic evaluation. Five centres in southwest England and South Wales aim to recruit 316 (reduced from original target of 366) male domestic abuse perpetrators. These will be randomised 2:1 to a community-based domestic abuse perpetrator programme (DAPP) or usual care comparator with 12-month follow-up. Female partners/ex-partners will be invited to join the study. The intervention for men comprises 23 weekly sessions of a group programme delivered in voluntary sector domestic abuse services. The intervention for female partners/ex-partners is one-to-one support from a safety worker. Men allocated to usual care receive no intervention; however, they are free to access other services. Their partners/ex-partners will be signposted to support services. Data is collected at baseline, and 4, 8 and 12 months’ follow-up. The primary outcome is men’s self-reported abusive behaviour measured by the Abusive Behaviour Inventory (ABI-29) at 12 months. Secondary measures include physical and mental health status and resource use alongside the abuse measure ABI (ABI-R) for partners/ex-partners and criminal justice contact for men. A mixed methods process evaluation and qualitative study will explore mechanisms of effectiveness, judge fidelity to the intervention model using interviews and group observations. The economic evaluation, over a 1-year time horizon from three perspectives (health and social care, public sector and society), will employ a cost-consequences framework reporting costs alongside economic outcomes (Quality-Adjusted Life Years derived from EQ-5D-5L, SF-12 and CHU-9D, and ICECAP-A) as well as the primary and other secondary outcomes. DISCUSSION: This trial will provide evidence of the (cost)effectiveness of a DAPP. The embedded process evaluation will further insights in the experiences and contexts of participants and their journey through a perpetrator programme, and the study will seek to address the omission in other studies of economic evaluations. TRIAL REGISTRATION: ISRCTN15804282, April 1, 2019 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-023-07612-6.