Many textbooks in educational measurement and classroom assessment have chapters devoted to specific item formats. There may be attempts to relate one item format to another, but the chapters and item formats are largely seem as distinct entities with only loose and uncertain connections. This paper synthesizes these discussions. An item format continuum is suggested. This continuum closely resembles the work of T. Rocklin (1992), R. Bennett (1993), and R. Snow (1993). There are seven broad categories of test items: (1) dialogue-oral; (2) performance; (3) project; (4) essay; (5) short answer; (6) multiple choice; and (7) true-false. Test validity has not been overlooked as a characteristic, but is simply not related to this continuum. Selecting an appropriate item format for a valid assessment of an instructional unit requires that the teacher match his or her objectives with item format characteristics. An appendix discusses the characteristics of the item formats in the continuum. (Contains 22 references.) (SLD)