IB-2004-F (March 2004)
Author: Linda Gorman
I. What is evidence-based medicine (EBM)?
Proponents like EBM originator David Sackett say evidence-based medicine is simply a tool to further the “conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient. It means integrating individual clinical expertise with the best available external clinical evidence from systematic research.”
II. So, who could possibly have a problem with using “the best evidence from systematic research?”
No one. That is what medicine does. The last 300 years of medical progress haven’t come about because physicians use Ouija boards to make decisions. But what, exactly, is “the best?” Real science is a messy social endeavor. It mixes observation, experiment, controlled trials, and seemingly farfetched proposals into an ongoing conversation that takes place in papers, meetings, talks, informal conversations, and formal education. Progress occurs when the good ideas are separated from the bad ones through a process of ruling out other possible explanations. Over time, informed judgment, careful observation, repeated trials, elegant
experiments, inelegant experiments, and pure serendipity have uncovered the medical miracles we now take for granted.
Evidence-based medicine proponents think that imposing their standards on physicians will improve clinical treatment. In the normal course of scientific inquiry, physicians will voluntarily adopt EBM standards when they are convinced that they are an improvement. But converting physicians takes clear and convincing evidence, and amassing that takes time. Envidencebased medicine proponents are impatient with the messy discursiveness of real scientific inquiry. They seek to streamline it by having the law empower a handful of experts to dictate which sources of information clinical practitioners must revere and which can be safely ignored. A typical information hierarchy from the University of Washington’s evidencebased toolkit is shown below.
Cochrane systematic reviews are systematized meta-analyses, studies in which researchers use a specific process when they combine a number of different study results into one overall conclusion. “Other SRs and Meta-Analyses” refers to combination reviews done by organizations other than the Cochrane Collaboration.
Evidence guidelines are papers containing their recommendations for best practices. Evidence summaries explain what is and is not known about a particular problem. RCT stands for randomized controlled trials, studies that use statistical techniques to compare results when two similar groups of patients receive different treatments.
Evidence-based medicine proponents are comfortable discarding evidence that does not come from randomized controlled trials and meta-analysis. In fact, Sackett and his co-authors advised people to ignore observational studies. “If you find that [a] study was not randomized,” they wrote, “we’d suggest that you stop reading it and go on to the next article.”1