Ray Hyman discovered many methodological errors with Schwartz's research including; "Inappropriate control comparisons", "Failure to use double-blind procedures", "Creating non-falsifiable outcomes by reinterpreting failures as successes" and "Failure to independently check on facts the sitters endorsed as true". Hyman wrote "Even if the research program were not compromised by these defects, the claims being made would require replication by independent investigators." Hyman criticizes Schwartz's decision to publish his results without gathering "evidence for their hypothesis that would meet generally accepted scientific criteria... they have lost credibility." https://drive.google.com/file/d/1Xu0W0POfxRw_GQ0LSksyCLGSS7k1bzl_/view?usp=sharing
After her death in the 1980s the medium Doris Stokes was accused of fraud, by author and investigator Ian Wilson. Wilson stated that Mrs Stokes planted specific people in her audience and did prior research into her sitters. Rita Goold a physical medium during the 1980s was accused of fraud, by the psychical researcher Tony Cornell. He claimed she would dress up as the spirits in her séances and would play music during them which provided cover for her to change clothes.
^ "Glossary of Key Words Frequently Used in Parapsychology" Archived 2010-12-24 at the Wayback Machine, Parapsychological Association website. "Materialization: A phenomenon of physical mediumship in which living entities or inanimate objects are caused to take form, sometimes from ectoplasm." Retrieved January 24, 2006 "Medium – Definition". Dictionary.com. Retrieved 23 March 2007.