Evidence-Based Medicine is a relatively new movement that seeks to put clinical med- icine on a firmer scientific footing. I take it as uncontroversial that medical practice should be based on best evidence-the interesting questions concern the details. This paper tries to move towards a coherent and unified account of best evidence in medicine, by exploring in particular the EBM position on RCTs (randomized controlled trials).

Evidence-Based Medicine is a relatively new movement that seeks to put clinical medicine on a firmer scientific footing. I take it as uncontroversial that medical practice should be based on best evidence—the interesting questions concern the details. This paper tries to move towards a coherent and unified account of best evidence in medicine, by exploring in particular the EBM position on RCTs.

The claims of RCTs to be the gold standard rest on the fact that the ideal RCT is a deductive method: if the assumptions of the test are met, a positive result implies the appropriate causal conclusion. This is a feature that RCTs share with a variety of other methods, which thus have equal claim to being a gold standard. This paper describes some of these other deductive methods and also some useful non-deductive methods, including the hypothetico-deductive method. It argues (...) that with all deductive methods, the benefit that the conclusions follow deductively in the ideal case comes with a great cost: narrowness of scope. This is an instance of the familiar trade-off between internal and external validity. RCTs have high internal validity but the formal methodology puts severe constraints on the assumptions a target population must meet to justify exporting a conclusion from the test population to the target. The paper reviews one such set of assumptions to show the kind of knowledge required. The overall conclusion is that to draw causal inferences about a target population, which method is best depends case-by-case on what background knowledge we have or can come to obtain. There is no gold standard. (shrink)

In clinical and agricultural trials, there is the danger that an experimental outcome appears to arise from the causal process or treatment one is interested in when, in reality, it was produced by some extraneous variation in the experimental conditions. The remedy prescribed by classical statisticians involves the procedure of randomization, whose effectiveness and appropriateness is criticized. An alternative, Bayesian analysis of experimental design, is shown, on the other hand, to provide a coherent and intuitively satisfactory solution to the problem.

Ethics and epistemology in medicine are more closely and more interestingly intertwined than is usually recognized. To explore this relationship, I present a case study, clinical trials of extracorporeal membrane oxygenation (ECMO; an intervention for persistent pulmonary hypertension of the newborn).Three separate ethical issues that arise from this case study-whether or not it is ethical to perform a certain trial at all, whether stopping rules for trials are ethically mandated, and the issue of informed consent-are all shown to be intimately (...) related to epistemological judgments about the weight of evidence. Although ethical issues cannot, of course, be resolved by consideration of epistemological findings, I argue that no informed view of the ethical issues that are raised can be adopted without first taking an informed view of the evidential-epistemological ones. (shrink)

Chronic diseases are recognized as a leadingcause of mortality, morbidity, health careutilization and cost. A constant tailoring ofcare to the actual needs of individualpatients, complexity and long duration are thedistinguishing features of chronic diseasemanagement.