It is becoming widely accepted that research which considers only the outcome and not the costs associated with new technologies in health care, is of limited value in making decisions about the use of scarce resources. Economic evaluation is becoming a standard feature of clinical research but many published economic evaluations fall short of best practice in their methodology. We have described the essential features of economic evaluation, using published studies in orthopaedics, in order to try to improve the ability of orthopaedic surgeons to read, understand and appraise such studies critically, and to encourage them to consider including economic evaluation in future investigations.