Sustaining motivational interviewing: a meta-analysis of training studies

Background and aims: Previous research indicates that motivational interviewing (MI) skills decline over time among participants in training workshops when post-workshop feedback and coaching are not provided. This study explored moderators of skill retention among trainees learning MI mainly for substance use disorder treatment in real-world treatment settings, including workshop enhancements and type and dose of post-workshop feedback and coaching.

Methods: A meta-analysis of training studies was conducted with studies that reported MI skills using observational measures and that included trainees from real-world agency settings. Standardized change scores were calculated to indicate the magnitude of pre-post training change in MI skills; standardized change scores from post-training to 3 and 6+ months follow-up were calculated to indicate the sustainability of training gains over time. Effect sizes were aggregated using random effects models.

Results: Twenty-one papers that reported the effects of MI training on agency staff were included in this review. Across studies, training yielded gains in MI skills (d = 0.76). Studies that did not include feedback and/or coaching reported eroding skills over a 6-month follow-up (d = -0.30), whereas post-workshop feedback/coaching sustained skills (d = 0.03). Effects of post-workshop feedback/coaching were moderated by frequency, duration and length of training. Moreover, studies reporting low levels of attrition from training protocols showed small increases in skills over the 6-month follow-up period (d = 0.12), whereas studies with high attrition showed skill erosion (d = -0.29).

Conclusions: On average, three to four feedback/coaching sessions over a 6-month period sustain skills among trainees for motivational interviewing, mainly for substance use disorder treatment. However, high rates of attrition from feedback/coaching contributes to post-workshop skill erosion.