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“Double blind, you are the weakest link — goodbye!”
  1. PJ Devereaux, MD1,
  2. Mohit Bhandari, MD, MSC1,
  3. Victor M Montori, MD, MSC2,
  4. Braden J Manns, MD3,
  5. William A Ghali, MD, MPH3,
  6. Gordon H Guyatt, MD, MSC4
  1. 1McMaster University Hamilton, Ontario, Canada
  2. 2Mayo Clinic Rochester, Minnesota, USA
  3. 3University of Calgary Calgary, Alberta, Canada
  4. 4McMaster University Hamilton, Ontario, Canada

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Double blind is the term researchers frequently use, and readers frequently accept, as a key marker of validity of a randomised controlled trial (RCT). Clinical trial experts and clinicians, when asked, all claim to “know” what double blind means; unfortunately it means diverse things to those questioned.1 The term lacks consistency in its use and interpretation — a critical flaw for any technical term if it is to be understood. In this editorial, we advocate abandoning the current blinding lexicon (ie, single, double, and triple blinding) and recommend transparent reporting of the blinding status of each group involved in the execution, monitoring, and reporting of clinical trials.

Blinding (or masking) in RCTs is the process of withholding information about treatment allocation from those who could potentially be influenced by this information. Blinding has long been considered an important safeguard against bias. Benjamin Franklin, in 1784, was probably the first to use blinding in scientific experimentation.2 Louis XVI commissioned Franklin to evaluate …

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  • This editorial appears in ACP Journal Club, Evidence-Based Mental Health, and Evidence-Based Medicine.