Technology assessment in medicine.

The author defines the concepts medical technology and technology assessment and presents a paradigm for the evaluation of medical technologies. He proposes a hierarchical assessment scheme in which level I, biologic plausibility, compares the technology's proposed mode of action with current biologic information and theory. Level II, technical feasibility, determines whether the technology can be delivered to the target population. Level III, intermediate outcomes, assesses whether the technology has a short-term impact on the biologic or physiologic process that is diseased. Level IV, patient outcomes, investigates the overall medical, psychologic, and financial impacts of the technology upon the patient, including unintended side effects and long-term morbidity and mortality. Level V, societal outcomes, measures the cost of the technology to society in terms of resource use, ethical issues, and social and political hazards. As an example, the author employs this scheme to analyze the use of screening tests for hypercholesterolemia.