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Can expert bias be reduced in medical guidelines?

BMJ 2019; 367 doi: (Published 09 December 2019) Cite this as: BMJ 2019;367:l6882
  1. Sheldon Greenfield, executive co-director
  1. Health Policy Research Institute at the University of California, USA
  1. sgreenfi{at}

There is an urgent imperative to generate and update accurate, unbiased, clinical practice guidelines, says Sheldon Greenfield

Despite robust study designs, even double blind randomised controlled trials can be subject to subtle forms of bias. This can be because of the financial conflicts of interest of the authors, intellectual or disciplinary based opinions, pressure on researchers from sponsors, or conflicting values. For example, some researchers may favour mortality over quality of life as a primary outcome, demonstrating a value conflict. The quality of evidence is often uneven and can include underappreciated sources of bias. This makes interpreting the evidence difficult, which results in guideline developers turning to “experts” to translate it into clinical practice recommendations.

Can we be confident that these experts are objective and free of bias? A 2011 Institute of Medicine (now known as the National Academy of Medicine) report1 challenged the assumption of objectivity among guideline development experts. Members of the …

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