This digest offers principles of performance assessment as an alternative to norm-referenced tests. The definition of performance assessment developed by the U.S. Congress's Office of Technology and Assessment is given, common features are listed, and the terms "performance" and "authentic" are defined. Suggested guidelines for addressing validity in performance assessments focus on internal characteristics of the assessment, the relationship of the measure to similar measures or future performance, and the intended effects of using the instrument. In providing evidence for the reliability and validity of performance assessment, evaluators are urged to address: (1) assessment as a curriculum event; (2) task content alignment with curriculum; (3) scoring and subsequent communications with consumers; and (4) linking and comparing results over time. Teachers are urged to use performance assessments in ways which will interact with instruction. (DB)