Approaches used in conducting health outcomes and effectiveness research

Over the past several decades, a number of approaches (e.g., decision analysis, meta-analyses, clinical trials, analysis of claims data, longitudinal observational studies including those done through patient outcomes research teams, etc.) have been used to conduct outcomes, effectiveness, and appropriateness research. Each of these approaches has varying degrees of comparative advantage and disadvantage with respect to the other. As knowledge of outcomes and effectiveness increases, and as new issues emerge as subjects of research, these approaches may or may not be adequate to generate the necessary information and level of confidence in findings that are desired. What are the strengths and weaknesses of each approach, and what gaps exist in our methodological armamentarium? How do existing methods need to be strengthened? What is the most appropriate application of specific research methods to particular problems? What is the appropriate balance of use of the different available approaches? What types of new methodologies need to be developed to further the field of outcomes and effectiveness research?