Occupational therapists are becoming increasingly aware of the importance of providing intervention that can be accurately measured and documented. Standardized evaluations not only provide a uniform administration and scoring procedure, but also allow for a comparison of an individual's performance to that of a normative sample. The effective and ethical use of standardized test scores requires that the examiner be proficient in test administration and understand the basic measurement and statistical concepts behind the interpretation process. This article addresses concepts relevant to the critical evaluation of a standardized test.