Development of the CoMTAS-Conversational Model Therapy Adherence Scale

Measuring adherence to a given psychotherapeutic approach has numerous benefits, such as ensuring therapist fidelity in the reporting of patient outcomes, the verification of therapist expertise, and facilitating the training of new psychotherapists by minimizing the cognitive load within a complex skillset. The Conversational Model Therapy Adherence Scale (CoMTAS) was developed by Russell Meares, one of the founders of Conversational Model Therapy (CMT). Further refinement of the CoMTAS involved consultation with Meares and several workshops with senior clinicians. Pilot testing followed with expert and novice CMT clinicians rating gold standard CMT recordings, more robustly diverse therapy recordings of novice therapists, and also recordings where the raters were blind to the identity of the therapist and patient. The CoMTAS showed consistently high inter-rater reliability and test-retest reliability over a period of 11 weeks. Furthermore, expert clinicians rated similarly with novice clinicians, thereby suggesting that minimal training in CMT is required to make reliably valid judgements of CMT adherence on the CoMTAS.