Ablind orblinded experiment is atest or experiment in where the experimenter does not know which treatment is given to asubject. The idea is to avoidbias which the experimenter might otherwise introduce.[1] If both tester and subject are blinded, the trial is adouble-blind trial.
Suppose consumers are asked to compare the tastes of different brands of a product. Obviously, the identities of the product should be hidden – otherwise consumers tend to prefer the brand they are familiar with. Similarly, when testing apharmaceuticaldrug, both patients and experimenter should not know the dosage being given in each case.
The opposite of a blind trial is an open trial. The termsblind (adjective) orto blind (transitive verb) when used in this sense are figurative extensions of the literal idea ofblindfolding someone.
Blind experiments went on to be used outside of purely scientific settings. In 1817, a committee of scientists and musicians compared aStradivarius violin to one with a guitar-like design made by the naval engineer François Chanot. A well-known violinist played each instrument while the committee listened in the next room to avoidprejudice.[2][3]
One of the first essays advocating a blinded approach to experiments in general came fromClaude Bernard in the latter half of the 19th century, who recommended splitting any scientific experiment between the theorist who conceives the experiment and a naive (and preferably uneducated) observer who registers the results without foreknowledge of the theory orhypothesis being tested. This suggestion contrasted starkly with the prevalentEnlightenment-era attitude that scientific observation can only be objectively valid when undertaken by a well-educated, informed scientist.[4]
Double-blind methods came into especial prominence in the mid-20th century.[5]
Double-blind describes an especially reliable way of conducting anexperiment. It tries to eliminate subjective, unrecognized biases carried by an experiment's subjectsand conductors.
In a double-blind experiment, neither the participants nor the researchers know which participants belong to thecontrol group, and which to the test group.Random assignment of test subjects to the experimental and control groups is the key to any double-blind research design. The information about who the subjects were, and which group they belonged to, is kept by a third party until the study is over.
Double-blind methods can be applied to any experimental situation in which there is a possibility that the results will be affected by conscious/unconsciousbias on the part of researchers, participants, or both.
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