The driving force behind my research and related scholarly activities has been my dedication to promoting the use of evidence-based psychosocial treatments in clinical settings. In the early 1990s, I began to apply motivational interviewing (MI) in the treatment of patients with severe mental illness and addictions. I engaged in a series of studies to develop this adaptation and empirically examined its treatment effects in a randomized clinical trial. At the time, few investigators had published about how to specifically apply MI to this dual diagnosis population and to test how well it worked. To my surprise, I found that MI was differentially effective with psychotically ill patients who abused cocaine, but not with those who abused marijuana. My work highlighted the complexities of enhancing motivation in patients with severe co-occurring mental illness and addiction. From these efforts to tailor MI, I became more interested in studying how to effectively train clinicians in evidence-based practices. I was impressed by the disciplined methods used to teach clinicians behavioral treatments in clinical trials (use of manuals, recording sessions, integrity rating, supervisory feedback and coaching, ongoing close monitoring of performance) and, ironically, how uncommon this careful training approach was employed in real world educational and practice settings. This simple observation led me to shift my research toward dissemination and implementation science, and I became increasingly involved in the NIDA Clinical Trials Network. Specifically, I assisted in the conduct of several national multi-site effectiveness trials involving MI. I had primary responsibility for serving as the local, and then national trainer, and developing an integrity rating scale and system to be used for supervision and independent observer treatment validation in the trials. I took the lead in psychometrically validating the scale and developing a NIDA-SAMHSA national dissemination product called Motivational Interviewing Assessment: Supervisory Tools for Enhancing Proficiency – a manual that details methods for supervising MI in community treatment programs. Subsequently, I became the national trainer-of-trainers for MIA: STEP and played a key role in its dissemination nationally and internationally. As a Principal Investigator, I am currently conducting a multi-site trial testing the effectiveness of MIA: STEP supervision on improving client outcomes and the extent to which clinician MI adherence and competence mediates this process. To my knowledge, this will be the first clinical trial directly testing the impact of any form of psychotherapy supervision on client outcomes. In addition, I have studied other strategies for training clinicians in evidence-based practices. I have published studies that have examined the effectiveness and cost effectiveness of a train-the-trainer approach for teaching community program clinicians behavioral treatments. I also have piloted an innovative stepwise approach in which clinicians only receive more intensive treatment training if they fail to meet a criterion performance threshold. The study showed the promise of more adaptive training program designs and suggested that future training trials screen participants to exclude those who already have the targeted skills and little room for improvement. In a recent publication, I reviewed the clinician training strategies literature and identify key areas that need more research.