Development of Motivational Interviewing Treatment Integrity (MITI) Fidelity Codes Assessing Motivational Interviewing with Couples.

This study evaluated preliminary reliability and validity evidence for novel scores that extend the motivational interviewing treatment integrity (MITI) coding system to assess elements unique to motivational interviewing (MI) with couples. We recruited 20 cismale couples where at least one partner was aged 18-29; reported substance use; and was HIV-negative. Couples were randomized to a three-session MI or attention-matched education control. Four coders rated audio-recordings of initial sessions in both conditions. Novel global scores had high nearly-exact percent agreement (Decreasing Dyadic Ambivalence = 100%; Facilitating Dyadic Functioning = 94%). Consistency for novel behavior counts was good (ICC = .72) and above minimum thresholds (nearly-exact agreement for Relationship Affirmations = 78%). MI sessions generated novel and established MITI codes that were significantly better than education sessions, providing preliminary evidence of validity. Findings provided initial support for the use of these novel scores in future research evaluating MI-based substance use and HIV risk reduction studies with couples.