Objective: The field of implementation science emphasizes efficient and effective fidelity measurement for research outcomes and feedback to support quality improvement. This paper reports on such a measure for motivational interviewing (MI), developed with rigorous methodology and with diverse samples.
Method: Using item response theory (IRT) methods and Rasch modeling, we analyzed coded (a) recordings (n = 99) of intervention sessions in a clinical trial of African American adolescents with obesity; (b) standard patient interactions (n = 370) in an implementation science study with youth living with HIV; and (c) standard patient interactions (n = 172) in a diverse community sample.
Results: These methods yielded a reliable and valid 12-item scale on several indicators using Rausch modeling including single construct dimensionality, strong item-session maps, good rating scale functionality, and item fit after revisions. However, absolute agreement was modest. The 12 items yielded thresholds for 4 categories: beginner, novice, intermediate and advanced.
Conclusions: The 12-item Motivational Interviewing Coach Rating Scale is the first efficient and effective fidelity measure appropriate with diverse ethnic groups, with interventions that are MI only or interventions that integrate MI with other interventions, and with adolescents and families as well as adults. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
Trial registration: ClinicalTrials.gov NCT01350531.