This thesis researched what characteristics of a training course influenced participants’ professional practice. The training this study evaluated was MarylandOnline’s Certificate for Online Adjunct Teaching (COAT) course. The COAT project began in 2008 when instructional designers from various higher education institutions collaborated on developing training for instructors who were making the transition to online teaching. Using a design-based research methodological approach within an interpretivist research paradigm, this study used mixed methods data collection tools and grounded theory data analysis techniques to evaluate whether the COAT course effectively helped the target audience of higher education adjunct faculty make the transition to online teaching. This study found that not only adjuncts with no online teaching experience, but also experienced online instructors, full-time faculty, and nonteaching professionals completed the COAT course. Research participants identified that the experience of being situated as students in an authentic online course focused on online teaching and learning influenced their later online teaching, campus-based teaching, and nonteaching professional practice. Focus group participants cocreated an observation protocol that was applied to archived courses taught by COAT alumni, and it was found that instructors, as reflective practitioners, took from their COAT experience instructional approaches and competencies that were appropriate for their specific teaching situations. Although limited to a particular context, the original contribution to scholarship of this study was the articulation of design principles and a conceptual framework that may be useful to researchers and practitioners working in the area of online instructor training. / 2013, 04