Development of a scale to measure fidelity to manualized group-based cognitive behavioural interventions for people with intellectual disabilities Andrew Jahoda a , Paul Willner b,e, *, John Rose c,g , Biza Stenfert Kroese c , Claire Lammie a , Jennifer Shead g , Christopher Woodgate e , David Gillespie d , Julia Townson d , David Felce f , Aimee Stimpson e , Nikki Rose g , Pamela MacMahon a , Jacqueline Nuttall d , Kerenza Hood d a Institute of Health and Wellbeing, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK b Psychology Department, College of Human and Health Sciences, Swansea University, UK c School of Psychology, University of Birmingham, UK d South East Wales Trials Unit, Institute of Translation Innovation, Methodology and Engagement, Cardiff University, UK e Directorate of Learning Disability Services, Abertawe Bro Morgannwg University Health Board, UK f Psychological Medicine and Neurology, School of Medicine, Cardiff University, UK g Black Country Foundation Partnership Trust, UK 1. Introduction Cognitive-behavioural therapy (CBT) is the treatment of choice for many psychological disorders (DoH/CSIP, 2007; Roth & Fonagy, 2004). However, there is evidence that the effectiveness of therapeutic interventions decreases as therapies move from university-based research studies into routine clinical practice (Curtis, Ronan, & Borduin, 2004; Henggeler, 2004). In some cases, interventions that appear clearly efficacious may be ineffective in a community setting (Stevens, Glasgow, Hollis, & Mount, 2000), although equivalent outcomes may also sometimes be reported (Houghton, Saxon, Bradburn, Ricketts, & Hardy, 2010). The generally accepted ‘technology model’ of psychotherapy research (Carroll & Rounsaville, 1990; Waskow, 1984) involves three elements: specification of treatments in manuals; training and supervision of therapists to ensure that Research in Developmental Disabilities 34 (2013) 4210–4221 A R T I C L E I N F O Article history: Received 10 June 2013 Received in revised form 3 September 2013 Accepted 3 September 2013 Available online 27 September 2013 Keywords: Fidelity Manual Cognitive-behavioural therapy Group Intellectual disability A B S T R A C T The context for the present study was a cluster-randomized controlled trial of a group- based anger-management intervention, delivered by day-service staff. We aimed to develop a scale to measure the fidelity of manualized cognitive-behavioural therapy (CBT) delivered to adults with intellectual disabilities in group-based settings. A 30-item monitoring instrument (the MAnualized Group Intervention Check: MAGIC) was adapted from an existing fidelity-monitor instrument for individual CBT. Two sessions for 27 groups were observed by pairs of monitors who had no other contact with the intervention. 16 observers participated, in 15 unique pairings. Observers recorded high levels of inter-rater reliability and the scale had good internal consistency. Fidelity ratings predicted two key outcomes of the intervention, and were themselves predicted by the therapists’ clinical supervisors. ß 2013 Elsevier Ltd. All rights reserved. * Corresponding author at: Psychology Department, Swansea University, Singleton Park, Swansea SA2 8PP, UK. Tel.: +44 1792 295278. E-mail address: p.willner@swansea.ac.uk (P. Willner). Contents lists available at ScienceDirect Research in Developmental Disabilities 0891-4222/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ridd.2013.09.006