The blind leading the blind: use and misuse of blinding in randomized controlled trials

Contemp Clin Trials. 2011 Mar;32(2):240-3. doi: 10.1016/j.cct.2010.11.004. Epub 2010 Nov 9.


The use of blinding strengthens the credibility of randomized controlled trials (RCTs) by minimizing bias. However, there is confusion surrounding the definition of blinding as well as the terms single, double, and triple blind. It has been suggested that these terms should be discontinued due to their broad misinterpretation. We recommend that, instead of abandoning the use of these terms, explicit definitions of blinding should be adopted. We address herein the concept of blinding, propose standard definitions for the consistent use of these terms, and detail when different types of blinding should be utilized. Standardizing the definition of blinding and utilizing proper blinding methods will improve the quality and clarity of reporting in RCTs.

MeSH terms

  • Data Interpretation, Statistical
  • Double-Blind Method*
  • Humans
  • Randomized Controlled Trials as Topic / methods*
  • Randomized Controlled Trials as Topic / standards
  • Single-Blind Method*
  • Terminology as Topic