"...For years I had thought that the real measure of the effectiveness of a course was the gains of the students, from their "initial condition" at entry to their "final state" at the end...Candace Schau...convinced me that we needed a "misconceptions measure" for a pre- and post-test...We labored on the Astronomy Diagnostic Test (ADT) for four semesters...I did not realize until a year after the final effort that we were developing the astronomical version of something like the Force Concept Inventory... "
