Abstract
The Astronomy Diagnostic Test (ADT) is the first research-based assessment tool developed for use in undergraduate introductory astronomy classrooms. The ADT National Project has rigorously measured reliability and validity through the collection and analysis of a large sample of student ADT results. The following was presented as part of the Special Session, “The Astronomy Diagnostic Test: Development, Results, and Applications” at the January 2002 Meeting of the American Astronomical Society