Why do professionals disagree? The case of hormone replacement therapy and coronary heart disease prevention

Why have professionals disagreed about whether midlife women should be advised to use hormone replacement therapy (HRT) for prevention of coronary heart disease (CHD)? Because the evidence has been incomplete and could be interpreted differently by different professionals, the question with regard to HRT and CHD prevention thus is not "What does the evidence prove?" but rather is "What are the decision rules by which research can be evaluated and made sense of?" The present article attempts to clarify the problem by cataloging dimensions along which professionals differ. These dimensions include the weight to be given to epidemiological vs. clinical trial data; whether a conclusion has already been drawn based on available evidence; whether a theoretical rationale exists; whether a professional is oriented to clinical work or research; and whether data is distorted.