Criticisms of evidence-based medicine.

More than twenty years after its conception, 'evidence-based medicine' (EBM) continues to invoke polarised debate. There are several areas of disagreement between EBM supporters and detractors as well as unanswered questions about the role of EBM in modern healthcare. Proponents suggest that the goal of EBM is to rescue medicine from many of its major ills, including wide variations in clinical practice, use of unproven interventions , and failure to apply consistent practice guidelines. Opponents disagree that EBM adequately addresses these issues, and dismiss EBM on the grounds of philosophical and practical flaws. This editorial briefly summarises the criticisms of EBM under five main themes, to provide a starting point for more focused discussion. The first type of criticism involves the philosophical underpinnings of EBM, which is based on empiricism. In its rawest form, EBM elevates experimental evidence to primary importance over pathophysiological and other forms of knowledge, and implicitly assumes that scientific observations can be made independent of the theories and biases of the observer. However, since the late 19th century, philosophers and scientists have been aware that making theory-free, objective observation is impossible. All observations are affected by the world view of the observer. 1 In fact, the preferred situation is for ''clinical trials to provide evidence in support of theory''. 2 Clearer observations allow for theory to be challenged and eventually replaced by better theory. Better theory allows for more specific, more detailed, and ultimately more useful observations. EBM ignores this essential interplay between observation and theory, disregarding the history and philosophy of science. 3 The second theme is that the definition of evidence within EBM is narrow and excludes information important to clinicians. 4,5 EBM grades evidence according to the methods used to collect it. Certain types of studies, such as randomised trials, are thought to be less vulnerable to bias and therefore 'better' evidence. 3,6 However, rando-mised trials and meta-analysis have not been found to be more reliable than other research methods. 3,7,8 The EBM definition of high quality evidence excludes information necessary to address many kinds of medically relevant questions. 9 In addition, EBM does not provide a means to integrate other, non statistical, forms of medical information, such as professional experience and patient specific factors. 3,4,10 Third, EBM is not 'evidence-based' because it does not meet its own empirical tests for efficacy. 3,11,12 Considering that EBM proposes that patient care can be improved …