To understand what a concept is, we must also understand what it is not. In this episode, Bill Goffe joins us to discuss his study of the effect of the use of negative examples on student learning outcomes. Bill is a Teaching Professor in the Economics Department at Penn State.  He had previously been one of our colleagues here at SUNY Oswego. Bill is very well known in the profession for his Resources for Economists on the Internet, which was one of the very first internet guides available for economists, and it’s now hosted and sponsored by the American Economic Association. He has served as a member of the American Economic Association’s Committee on Economic Education, the Secretary-Treasurer for the Society of Computational Economics, an Associate Editor for Computational Economics and the online section of the Journal of Economic Education. Bill is currently co-chair of the Liberal Arts Teaching Group, a faculty learning community at Penn State. A transcript of this episode and show notes may be found at http://teaforteaching.com.