The effectiveness initiative II: The spectrum of effectiveness research.

Effectiveness research aims to base medical decision making more on rigorous evidence than on intuition and anecdote. The methods used to generate new data include, in order of decreasing rigor, clinical trials, observational studies, claims data analysis, and anecdotal studies. The methods that synthesize existing data include unstructured literature reviews, consensus development, meta-analysis, and decision modeling. Cost minimization, cost-effectiveness, and cost-benefit analyses are formal methods of incorporating the economic impact of alternative medical interventions.