Blind — An experiment where the subject does not know whether he is receiving the treatment (“experimental group”) or a placebo (“control group”).
Double blind — A more stringent method, where neither the subject nor the persons conducting the experiment know which persons are experimentals, which controls. (It is however useful that someone should know, or have scribbled down somewhere, who is in which group, or otherwise analyzing the results can be difficult.)
Triple blind — As previous, but in addition those that request the study for reading do not know if they are reading it or a “dummy study”, which while outwardly scientific is subtly flawed so that it contains no actual useful results at all. (The dummy study method, pioneered by Reinhardt de Cam, is dependant on the existence of very carefully flawed and inert dummy studies, prepared in a wide variety of so-called “CAM institutions” around the world.)
Quadruple blind — In this very unusual method four key groups (experimentees, experimenters, scientifically literate readers, the press) are kept in the dark until all pertinent persons that were involved with the experiment are dead. Then all uncomfortable and shameful details of the study can be revealed without anyone’s livelihood being ruined. The genius of quadruple blinding is the study is kept topical until the reveal, and the public’s appetite for it is whetted, because of whisperings of the “jungle drum” of the “unofficial” people not in the four key groups. (Studies of this category allegedly include “The Philadelphia Experiment”, “The Browne Psychic Impersonator Project”, and “The Stanford Reality TV Experiment”.)
Quintuple blind — There is no study. Its existence is universally denied. Bloggers are not permitted to admit the study exists. There are consequences. There is no study. That is all.
* * *
There is also a rude and crude bit of physicians’ terminology which utilizes the first three terms above, viz. “blind” = one eye missing, “double blind” = both eyes missing, “triple blind” = both eyes missing and arsehole sewn shut.
This terminology, though necessary during the period of the Napoleonic wars and the revolutionary cruelty of the French troops, has since fallen into disuse.