This episode explores the development and application of the Motivational Interviewing Treatment Integrity code (MITI), a tool for measuring the fidelity of motivational interviewing (MI) in clinical practice and research. Against the backdrop of Denise Ernst's 30-year career in MI, the discussion traces the evolution of MI coding from its early, cumbersome forms to the more streamlined MITI. More significantly, the conversation highlights the bi-directional relationship between the MITI and MI research, with the instrument informing research and vice-versa. For instance, the recent inclusion of "softening sustained talk" in MITI 4 reflects evolving research on client language and its impact on outcomes. The podcast also delves into the use of MITI as an educational tool, emphasizing the importance of reflective listening and the identification of client language indicative of change. Ultimately, this episode underscores the value of self-reflection and deliberate practice in enhancing MI skills, offering practical advice for clinicians seeking to improve their practice through coding and feedback.