This report describes a hierarchical classification system for clinical endpoints in diagnostic technology assessment. The model requires classification of investigative outcomes into 1 of 6 categories, including technical efficacy, diagnostic accuracy efficacy, diagnostic thinking efficacy, therapeutic efficacy, clinical outcome efficacy, and societal efficacy. Evaluations at successive levels indicate a broader understanding of the test's value. The purpose of this classification system is to help readers of the medical literature consider various aspects of test performance, and to identify aspects of a test that require additional investigation. It is also designed to be used as a template for systematic reviews of diagnostic tests. In this review, examples from the medical literature are discussed to highlight important concepts from the hierarchy model and their relevance to emergency medicine.