Methodological Problems in Free-Response ESP Experiments

Various methodological problems have occurred in some recent free-response experiments in parapsychology. Statistical errors have involved improper assumptions of independence, multiple analysis of data, and, to a lesser extent, data selection and misapplication of the normal approximation to the binomial. The inability to accurately measure information in free-response judging procedures has led to a general lack of statistical sensitivity and to incorrect inferences about ESP "information rates." Further, the possibility of sensory cues has not been completely eliminated in several experiments. Most of these problems can be easily avoided with slight alterations in experimental