Abstract
OBJECTIVES: To evaluate the impact of a motivational interviewing (MI) training program for prison professionals by analysing the progression of MI-compatible competence and adherence, as well as the reduction of non-compatible practices. MATERIAL AND METHOD: A longitudinal quasi-experimental study with repeated measures was conducted over four months at three time points. A total of 25 correctional professionals participated in a three-phase training program. A Spanish-translated version of the Motivational Interviewing Assessment: Supervisory Tools for Enhancing Proficiency (MIA:STEP) questionnaire from Substance Abuse and Mental Health Services Administration (SAMHSA) was used for self-assessment. Statistical analyses included repeated measures ANOVA, Friedman's test, effect size (h(2)), and observed power. RESULTS: Non-compatible adherence to MI significantly decreased (p <0.001, h(2) = 0.360; c(2) = 20.796, p <0.001), representing the most notable finding. Compatible competence in MI showed a non-significant increase in ANOVA (p = 0.138), but a significant improvement in Friedman's test (c(2) = 9.621, p = 0.008). Compatible adherence initially increased (p <0.001, h(2) = 0.267) but subsequently declined (c(2) = 9.939, p = 0.007). Non-compatible competence significantly increased between the initial and final assessments (p = 0.012, h(2) = 0.169; c(2) = 9.711, p = 0.008). DISCUSSION: The program was effective in significantly reducing non-compatible adherence to MI, which emerged as the most substantial outcome. While compatible adherence fluctuated and compatible competence exhibited a differentiated progression depending on the statistical test used, the findings indicate progressive learning and areas requiring further reinforcement. The ecological validity of the study design strengthens the applicability of the results, providing evidence of the impact of MI training in correctional settings.The study was approved by the Ethics Committee of the University of Salamanca (CEISH).