Blinding

Abstract The objective of blinding is to contribute to the elimination of bias that may be introduced intentionally or unintentionally by the various individuals involved in a research study. Different types of bias (e.g., information bias, detection bias, etc.) can be prevented or reduced by blinding patients, health care providers, data collectors, outcome assessors, and/or data analysts. Even when patients and those administering treatment cannot be blinded (e.g., if the study involves a surgical procedure), blinding of outcome assessment can still be possible and helps reduce detection bias. Owing to ambiguity in blinding methodology (e.g., single‐blinded, double‐blinded, etc.), it is important to carefully report the blinding status of all individuals involved in a research study and the blinding mechanism. This helps the reader judge the validity of the study and ensures the credibility of its results. In order to ensure the success of blinding in preventing or reducing bias, it is important to assess its efficacy before the study begins. However, assessment of the efficacy of blinding at the end of the study might produce ambiguous results as failures in blinding are often confounded with treatment efficacy and adverse events.