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Evidence-Based Medicine (EBM)

A guide to evidence-based medicine resources in UVic Libraries.

Applying the Evidence

In the application of the evidence obtained and vetted in the previous steps, the first question to ask is:

Can valid results be applied to this particular patient?

Once you have appraised a systematic review or primary study you need to decide whether or not it's findings can be applied to your specific patient. In doing so, you should take into account your patient's unique characteristics, circumstances, and personal preferences.

Questions to ask in clinical decision making:

Interventions (including systematic reviews of intervention studies and studies of risk/harm)

  • Is my patient different from those described in the study so that the results of the study are not applicable?
  • Is the treatment feasible in my practice setting?
  • What would be the potential benefits and harms (i.e. side-effects) for my patient from this treatment?
  • What are my patient's values and expectations for both the outcome I am trying to prevent and the treatment on offer?

Diagnostic tests

  • Is the test available, affordable, accurate, and precise in this setting?
  • Can I generate a clinically sensible estimate of my patient's pre-test probability?
  • Will the resulting post-test probabilities affect my management and help my patient?


  • Are the study patients similar to my patient?
  • Will this evidence make a clinically important impact on my conclusions as to what to tell the patient?

According to Sackett and Orman, it is important as practitioners keep in mind that guidelines require both general (external evidence) information and specific (local circumstance) information plus good judgment. In addition to paying close scrutiny to the quality of evidence, the local applicability of a guideline depends on the extent to which it is harmony or conflict with patient-specific factors. These factors are summarized below:

The Killer Bs
1.  Is the burden of illness (frequency in the community or the patient's pretest probability or expected event rate (PEER) too low to warrant implementation?
2. Are the beliefs of the Individual patients or communities about the value of the interventions or their consequences incompatible with the guideline?
3. Would the opportunity cost of implementing this guideline constitute a bad bargain in the use of our energy or our community's resources?
4. Are the barriers (geographic, organizational, traditional, authoritarian, legal, behavioural) so high that it is not worth trying to overcome them?

(Sackett & Orman,1999)

Clinical Practice Guidelines

Works Cited

​Sackett D, & Oxman A. Guidelines and killer Bs. BMJ Evidence-Based Medicine 1999;4:(4)100-101.

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This work by The University of Victoria Libraries is licensed under a Creative Commons Attribution 4.0 International License unless otherwise indicated when material has been used from other sources.