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Primary care
Shared decision is the only outcome that matters when it comes to evaluating evidence-based practice
  1. James McCormack1,
  2. Glyn Elwyn2
  1. 1 Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
  2. 2 The Dartmouth Institute for Health Policy & Clinical Practice, Lebanon, New Hampshire, USA
  1. Correspondence to Professor James McCormack, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; james.mccormack{at}

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Determining if a particular treatment improves important clinical outcomes such as symptoms, overall quality of life, incidence of CVD, mortality, among others typically requires well-designed randomised clinical trials. Once this type of evidence is available, clinicians can then use these treatments in day-to-day practice. Hopefully, we would all agree that almost all day-to-day healthcare decisions should be made at the level of each individual patient. Given that, we are becoming increasingly uneasy observing that evaluations of the impact of evidence-based practice (EBP) are invariably focused on improving population-level health outcomes (overall incidence of heart attacks or hospitalisations) rather than at the individual patient level.

We believe this focus is inappropriate and fundamentally flawed for the following reasons. 

Population-level health outcomes rarely if ever take into account patient values and preferences and therefore by definition fly directly in the face of the fundamental goals and definition of EBP. Ignoring patient values and preferences or at least not placing them at the forefront of decision making legitimises the argument that the presence of effects at population levels is sufficient justification for recommending treatments even though the absolute magnitude of these changes clearly may not be important to all individual patients.

It seems a frame-shift has taken place, where population-level metrics are being applied in error to a phenomenon that should be evaluated at an individual level. Figure 1 illustrates the two frames—one where interventions should, correctly, be evaluated by population-level outcomes, including morbidity, mortality and treatment effects, and the other showing that at the level of individuals, the right outcome is whether a decision informed by the best available evidence is aligned to a patient’s informed preference.

Figure 1 Population versus individual outcomes

To avoid continuing this individual-to-population frame-shift error, we suggest the key outcome for EBP evaluations should be primarily if not almost exclusively focused on shared …

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  • Contributors JM and GE contributed equally to the writing of this article.

  • Competing interests None declared.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.