Blinding

Reduce observation biases by blinding study participants, staff, and clinicians

Blinding is an empirical process used in randomized controlled trials to reduce observation bias. Blinding means that study participants, research staff, and/or clinicians do not know whether the treatment or control is being given in the empirical setting.

Types of blinding

The use of blinding strengthens the internal validity of a randomized controlled trial by ensuring that study participants are treated in a salient fashion, regardless of group assignment. Blinding assists in deterring well-documented research phenomena that introduce observation bias into randomized controlled trials like the Hawthorne effect, the Halo effect, diffusion of treatment, compensatory rivalry, and biased statistical analysis.

A randomized controlled trial can be single-blinded (study participants are blinded), double-blinded (study participants and research staff), or triple-blinded (study participants, research staff, and lead researchers and clinicians).
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There are three types of blinded research studies: Single-blinded, double-blinded, and triple-blinded.