double-blind
adj1
Describing an experiment (usually medical) in which some information which might influence the experiment is withheld from two parties. Most commonly, parties in question are the subjects and the administrators and the information which is withheld is the treatment groups of the subjects.
- The Clever Hans effect, however, can be eliminated by means of double-blind procedures, where the person administering or scoring a test given to an animal does not know the “correct” answer.1984, Philip Lieberman, The Biology and Evolution of Language, Harvard University Press, →ISBN, page 246: