BM (Blind Matching): Technique in which the subject matches a deck of ESP cards to five key cards which are laid out face down before him in an unknown order. Unless otherwise stated, the order is also unknown to the experimenter.

BT (Before Touching): Technique in which the top card of the face-down deck is called and, after being called, is laid aside for checking at the end of the run. Each card in the deck is treated in the same way. BT-5 represents the condition of checking after every 5 calls; BT-25 after the whole pack.

Clairvoyance: Extrasensory perception of objective events, as distinguished from telepathic perception (mind to mind communication).

CR (Critical Ratio): The observed deviation divided by the standard deviation.

Deck Matching = ESP shuffle or Psychic Shuffle: Technique in which the subject shuffles a deck (25 ESP cards)

DEVIATION: The amount an observed number of hits or an average score varies from the mean chance expectation or chance average. A deviation may be total (for a series or run) or average (per run).

DT (Down Through): The technique in which the cards are called down through the deck before any are removed or checked.

ESP: extra-sensory perception (without the aid of the five senses)

GESP: General (or undifferentiated) extra-sensory perception: Technique designed to test the occurrence of extra-sensory perception permitting either telepathy or clairvoyance, or both, to operate.

JP: Journal of Parapsychology, founded by J. B. Rhine in 1937.

KEY CARD: One of the five cards (where there are five suits) against which the cards of the test deck (i.e. target cards) in the matching tests (OM, BM, TM, etc.) are matched.

Matching: A form of calling in which a target card is placed opposite the key card which the subject selects to identify it.

np = Number of trials multiplied by the probability of succeeding on each trial, which gives the mean chance expectation

OM (Open Matching): The technique in which the subject matches a deck of ESP cards to five key cards which are face up before him.

P = p-value = probability of success in each trial.

PC (Pure Clairvoyance) = Clairvoyance: The word “pure” emphasizes the exclusion of telepathy.

p.e. = Probable Error of np. This is the deviation from np at which the odds are even that it was or was not due to mere chance.

P.R. Psychic research.

Precognition: The extra-sensory perception of an undetermined random future event.

Psycho-kinesis: the effect of mind affecting matter (as in dice work).

PT (Pure Telepathy) = Telepathy: The word “pure” emphasizes the exclusion of clairvoyance.

SBT = Screen Before Touching

SPR: Society of Psychical Research, founded in England 1882; the American branch (ASPR) was founded in 1884 in Boston.

STM (Screened Touch Matching): The touch matching technique with an upright screen preventing the subject from seeing the handling of the cards by the experimenter.

Target Card: The card which the percipient is attempting to perceive (i.e. to call, or otherwise indicate a knowledge of).

Telepathy: extra-sensory perception of the mental activities of another person (distinguished from clairvoyance).

Touch Matching: The technique in which the subject indicates his call by tapping or touching one of the five key cards while the experimenter places the target card thus called in front of the key card indicated.

X VALUE = Critical Ratio: The observed deviation divided by the standard deviation or by the probable error. When the deviation is 4 times the p.e. (X=4), the deviation is regarded as ‘significant,’ i.e. reliably showing a principle beyond ‘chance’ activity.