Blinding in statistics refers to the practice of concealing group allocation from one or more individuals involved in a clinical research study, most commonly a randomized controlled trial (RCT) . The purpose of blinding is to minimize the risk of bias that can arise from knowledge of group allocation, which can affect the results of the study. Blinding can be done on all the people involved in the clinical trials, including subjects, clinicians, data collectors, outcome adjudicators, and data analysts.
There are different types of blinding, including single-blind, double-blind, and triple-blind. In single-blind studies, the participants do not know which group they are in, while in double-blind studies, both the participants and the researchers involved with the participants are blinded. Triple-blind studies involve blinding the participants, researchers, and outcome assessors.
Blinding is especially important in subjective trials to avoid skewed results. For example, blinding is appropriate for pain relief studies. If a patient knows they are receiving a “real” drug, they will be more likely to report pain relief than those patients receiving a placebo. Blinding is less important in trials when there is a more objective criteria at stake, such as avoiding a patient’s death (for example, in cancer trials) .
Blinding can be challenging to implement, and it may not always be possible or practical. However, blinding is a critical part of RCTs, and it reduces the bias that affects the results.
