Medical technology assessment: adequate questions, appropriate methods, valuable answers.
Medical Technology Assessment begins with carefully posing the appropriate questions to be examined. Specification of the critical assessment provides the framework for the design to provide the answers. This paper addresses the Technology Assessment process as a sequence of the above steps. The practical requisites of the diversity of questions, the economic, and study design considerations generated are addressed in a systems analysis model of input-process-outcome. Applications and the relative merits of such design consideration are discussed and illustrated. The questions related to medical technologies may come from different groups of people directly or indirectly interested, and having active or passive relationship to a given technology. There are 4 basic issues from which the detailed questions derive. These are the issues of need, effectiveness, safety and cost. The timing of asking questions in the life-cycle of a technology and the adequacy of the answers determines the choice of methods, the extent of an evaluation and the quality of the responses. The reliability, external validity, generalizability, and the clarity of conclusions are the characteristics of a practical and valuable assessment.