Teaching development programs (TDPs) seem like a natural way to develop innovative teaching and learning environments. In the local programs of the authors, the participants do a project in the second semester of participation. In the project, the participants are required to plan, carry out, and evaluate some form of student centered teaching, and innovative teaching formats are encouraged and often developed. However, the wider institutional impact of these developments is difficult to assess. Even though a number of primarily quantitative studies show generally positive results, only small impacts are reported, and the question of why and how the programs work is not addressed. This study is based on 79 participant projects and interviews with 19 teachers of which 9 also did one of the participant projects. The data was analyzed in relation to specific learning outcome and level, types of teaching and innovation addressed, approaches to teaching (AT) using all 5 qualitative categories, self-efficacy beliefs (SEBs), institutional context of teaching , experience thereof, and strategies for dealing with it. Results show satisfactory outcome, and reveal interesting relationships between AT, SEBs and the institutional context, thereby providing insight into the why and how the program works and a basis for further development of the TDP.