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Criticism of experimental results

Critical analysts, including some parapsychologists, are unsatisfied with experimental parapsychology studies. Some reviewers, such as psychologist Ray Hyman, contend that apparently successful experimental results in psi research are more likely due to sloppy procedures, poorly trained researchers, or methodological flaws rather than to genuine psi effects. Fellow psychologist Stuart Vyse hearkens back to a time of data manipulation, now recognized as "p-hacking", as part of the issue. Within parapsychology there are disagreements over the results and methodology as well. For example, the experiments at the PEAR laboratory were criticized in a paper published by the Journal of Parapsychology in which parapsychologists independent from the PEAR laboratory concluded that these experiments "depart from criteria usually expected in formal scientific experimentation" due to "roblems with regard to randomization, statistical baselines, application of statistical models, agent coding of descriptor lists, feedback to percipients, sensory cues, and precautions against cheating." They felt that the originally stated significance values were "meaningless".

A typical measure of psi phenomena is a statistical deviation from chance expectation. However, critics point out that statistical deviation is, strictly speaking, only evidence of a statistical anomaly, and the cause of the deviation is not known. Hyman contends that even if psi experiments that regularly reproduce similar deviations from chance could be designed, they would not necessarily prove psychic functioning. Critics have coined the term The Psi Assumption to describe "the assumption that any significant departure from the laws of chance in a test of psychic ability is evidence that something anomalous or paranormal has occurred... assuming what they should be proving." These critics hold that concluding the existence of psychic phenomena based on chance deviation in inadequately designed experiments is affirming the consequent or begging the question.

In 1979, magician and debunker James Randi engineered a hoax, now referred to as Project Alpha to encourage a tightening of standards within the parapsychology community. Randi recruited two young magicians and sent them undercover to Washington University 's McDonnell Laboratory, where they "fooled researchers... into believing they had paranormal powers." The aim was to expose poor experimental methods and the credulity thought to be common in parapsychology. Randi has stated that both of his recruits deceived experimenters for three years with demonstrations of supposedly psychic abilities: blowing electric fuses sealed in a box, causing a lightweight paper rotor perched atop a needle to turn inside a bell jar, bending metal spoons sealed in a glass bottle, etc. The hoax by Randi raised ethical concerns in the scientific and parapsychology communities, eliciting criticism even among skeptical communities such as the Committee for the Scientific Investigation of Claims of the Paranormal (CSICOP), which he helped found, but also positive responses from the President of the Parapsychological Association Stanley Krippner. Psychologist Ray Hyman, a CSICOP member, called the results "counterproductive".