Six preservice social studies teachers examined techniques believed to promote active student engagement during a 12-week field experience through electronic portfolio development supported by evidential reasoning methods and reflective question prompts. These methods helped preservice teachers to broaden their definitions and observations of active student engagement, reexamine and modify teaching conclusions based on classroom evidence, and formulate improvement plans for future implementations. This paper provides results of this study as well as implications for future research using electronic portfolios to systematically inquire into teaching practices through reflection. (Contains 4 figures.)