This handbook is designed to assist teachers in using the Science Item Bank to construct diagnostic tests and end-of-course achievement tests. The item bank consists of over 2,800 multiple-choice items, and teachers are encouraged to supplement this source of test items with other forms of test questions. Key answers to these questions are arrived at by definition, by convention, or by consensus. In addition to their use in tests, these items may be used as stimuli for class discussion or for models for teacher-written items. The recommended process of test construction is based on classifying items on a content-by-cognitive process grid and using an iterative selection process until a satisfactory distribution of items is achieved. Classroom item analysis procedures are described for computing an item difficulty (facility) index, an item discrimination index, and an evaluation of distractors. The preparation of the item bank is described. The appendix includes detailed content outlines and a taxonomy of cognitive processes based on the work of Bloom and others, with sample items illustrative of the various categories. (CTM)