Excessive variability of the performance of schizophrenic subjects in experimental tasks has been noted so often since experimentation with these subjects (Ss) first began, that it is now widely accepted as a commonplace generally considered to be more annoying than meaningful. The excessive variability is usually found both within individuals and within groups of Ss. Usually, it has been interpreted as an indication of variable motivation, or of vacillation of attention. Such Ss have been described as uncooperative in some degree, as uninterested, or as distractible, and these attributes of S have been proposed to "explain" why he may have performed well one moment and poorly the next.
Historically, there have been 3 ways of dealing with this problem of excessive variability. The most common is to reckon it a fact of schizophrenic life and to deal with it statistically. Usually this
TAYLOR IA, ROSENTHAL D, SNYDER S. Variability in Schizophrenia. Arch Gen Psychiatry. 1963;8(2):163-168. doi:10.1001/archpsyc.1963.01720080053008