In a blind or<unk> , information which may influence the participants of the<unk>  is withheld until after the<unk>  is complete. Good blinding can reduce or eliminate<unk> al biases that arise from a participants' expectations, observer's effect on the participants, observer bias, confirmation bias, and other sources. A blind can be imposed on any participant of an<unk> , including subjects, researchers, technicians, data analysts, and evaluators. In some cases, while blinding would be useful, it is impossible or unethical. For example, it is not possible to blind a patient to their treatment in a physical therapy intervention. A good clinical protocol ensures that blinding is as effective as possible within ethical and practical constraints. During the course of an<unk> , a participant becomes unblinded if they deduce or otherwise obtain information that has been masked to them. For example, a patient who experiences a side effect may correctly guess their treatment, becoming unblinded. Unblinding is common in<unk> s, particularly in pharmacological trials. In particular, trials on pain medication and antidepressants are poorly<unk> . Unblinding that occurs before the conclusion of a study is a source of<unk> al error, as the bias that was eliminated by blinding is re-introduced. The CONSORT reporting guidelines recommend that all studies assess and report unblinding. In practice, very few studies do so. Blinding is an important tool of the scientific method, and is used in many fields of research. In some fields, such as medicine, it is considered essential. In clinical research, a trial that is not a<unk>  trial is called an open trial.
Blinded experiment
Multiple baseline design
Clinical study design
Solomon four-group design
In silico clinical trials
Analysis of clinical trials
Parallel study
N of 1 trial