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double-blind procedure-an experimental procedure in which neither the subjects of the experiment nor the persons administering the experiment know the critical aspects of the experiment; a double-blind procedure is used to guard against both experimenter bias and placebo effects.ouble-blind procedure-an experimental procedure in which neither the subjects of the experiment nor the persons administering the experiment know the critical aspects of the experiment; a double-blind procedure is used to guard against both experimenter bias and placebo effects.
blind. not having the sense of sight. See also blindness. double blind trial. an experiment in which the identity of the animals in the treatment and control groups is unknown to the experimenter and in addition the assessment of the results is done without the animals' identities being known to the experimenter.