A variety of methods are examined that teachers from preschool to graduate school levels can use in assessing their students; the common principles underlying classroom assessment are explored. The first principle is that the primary purpose of classroom assessment is to inform teaching and improve learning. A second principle is that multiple sources of information are necessary when assessing learning in the classroom. A third principle of classroom assessment concerns validity, reliability, and fairness. Once these principles are accepted, the selection of particular assessment methods should be based on desired learning outcomes, the purpose of the assessment, and audience for which it is intended. Assessment approaches that might be used include selected response items of the sort presented in multiple-choice, true-false, and matching tests and for performance-based approaches that include constructed responses, product assessment, performances, and process-focused assessment. In addition to making choices about classroom assessment methods, teachers should consider options for evaluating student work and for communicating assessment results. Various scales and reporting processes are discussed. An appendix contains a glossary of classroom assessment terms. (Contains 6 figures and 22 references.) (SLD)