Evidence Based Medicine is Usually defined as:

     "The conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. This practice means integrating individual clinical experience with the best available external clinical evidence from systematic research". (Sackett et al., BMJ, 1996, 312, pp.72-3) 

     Rather than reinventing the wheel, we refer readers to several online documents  which provide great insight into the meaning and purpose of EBM
 

• An Introduction to Evidence Based Practice:  From the Wisdom Center, Schefield, England
• Evidence Based Case Report:  An entertaining personal anecdote used to illustrate the application of EBM
• EBM vs Non-EBM:  A table comparing the two
• Seven Alternatives to EBM:  Mandatory reading

EBM hype and practice
     It is becoming ever more difficult to avoid self described  "Evidence Based"  documents in the print and electronic medical literature.  Indeed, the term is turning into somewhat of an academic elitist  catch phrase which is probably turning off a lot of people.   Even the CME industry is getting into the act.  However, many "evidence based" publications are simply review articles. 

     As clinicians working in very busy ambulatory and Emergency settings, we must take a liberal approach to EBM.  It is clearly impracticle to find, read, and review, RCT's and meta-analysis during the course of clinical care.  The definition phrase "best AVAILABLE evidence" really needs to be stressed.  All forms of evidence must be utilized (and scrutinized).    Real time access to good evidence, particularly critically appraised materials is the rate limiting step for practicing EBM in fast paced clinical settings.  Getting practitioners to buy into the concept and to understand the principals is another story.   The alternative to EBM (not using the best available evidence) is unacceptable. 

     Nevertheless, we are great enthusiasts of EBM.  It is difficult to deny the need for providing clinicians with good, usable, information and giving them the tools to apply it to patients (EBM in a nutshell).  In the near future it is very likely that web based hand held devices will make access to critically assessed medical literature available at the bedside.  This will make EBM eminently more feasible.   It will also provide more challenges for sorting out usable evidence from the hype.   As a guideline, we suggest you look for the following characteristics when reading a document which includes "Evidence Based"  in it's description.
 

• An evidence based report  provides critical assessment (preferably standardized) of the research methodology used in cited references.

• An evidence based document permits  the reader to determine the applicability of the evidence to specific patient  populations and to individual patients. This requires a description of the sample population on which the evidence was determined. 

• An evidence based description of research finding provides "hard" data, permitting readers to apply information from cited references directly to their patient.  This is often in the form of Number Needed to Treat (NNT), Likelihood Ratios (LR), or Number Needed to Harm (NNH) statistics. If these values are not provided you should be able to determine them from data made available.

• Look for documents which provide more than p values when describing the "significance" of results. Measures of effect size (RR, NNT, LR, NNH) with confidence intervals allow you to determine the clinical significance of research findings.