Over the course of his career Burt published numerous articles and books on a host of topics ranging from psychometrics to philosophy of science to parapsychology. It is his research in
behavior genetics, most notably in studying the heritability of intelligence (as measured in IQ tests) using
twin studies that have created the most controversy, frequently referred to as "the Burt Affair."
Shortly after Burt died it had become known that all of his notes and records had been burnt, and he was accused of
falsifying research data by
Leon Kamin. From the late 1970s it was generally accepted that "he had fabricated some of the data, though some of his earlier work remained unaffected by this revelation."<ref name="Encyclopedias" /</ref> This was due in large part to research by
Oliver Gillie (1976) and
Leon Kamin (1974). The possibility of fabrication was first brought to the attention of the scientific community when Kamin noticed that Burt's correlation coefficients of
Monozygotic and
Dizygotic twins' IQ scores were the same to three decimal places, across articles – even when new data were twice added to the sample of twins.
Leslie Hearnshaw, a close friend of Burt and his official biographer, concluded after examining the criticisms that most of Burt's data from after
World War II were unreliable or fraudulent.
J. Philippe Rushton, on the other hand, notes that Burt's controversial correlation for reared-apart identical twin's IQ scores is in line with the correlations found in modern studies.
In 1976 the London
Sunday Times claimed that two of Burt's supposed collaborators, Margaret Howard and J. Conway, were invented by Burt himself. They based this on the lack of independent articles published by them in scientific journals, and the fact that they allegedly only appeared in the historical record as reviewers of Burt's books in the
Journal of Statistical Psychology when the journal was redacted by Burt. However, Miss Howard was also mentioned in the membership list of the British Psychological Society, prof. John Cohen remembered her well during the 1930s and prof. Donald MacRae had personally received an article from her in 1949 and 1950. According to Ronald Fletcher there is also full documentary evidence of the existence of Miss Conway.
In 1989 and 1991, two independent authors,
Robert Joynson and
Ronald Fletcher published books that argued the case against Burt was led by "carelessness and errors of interpretation." They argued that explanations exist that are at least as plausible as the guilty explanations for each of the points of concern, such as that the bombing of Burt's University College during
World War II caused Burt to have to sort out his previous data.
In 1995, Cambridge University Professor of Psychology Nicholas Mackintosh edited the book
Cyril Burt: Fraud or Framed? (Oxford University Press), in which the contributors argued that "his defenders have sometimes, but by no means always, been correct, and that his critics have often jumped to hasty conclusions." A 1995 review in Nature concluded "...Mackintosh's academic whodunit marks a further step towards Burt's rehabilitation." However,
William H. Tucker argued in a 1997 article that: "A comparison of his twin sample with that from other well documented studies, however, leaves little doubt that he committed fraud."
http://www3.interscience.wiley.com/cgi-bin/abstract/45746/ABSTRACT
W.D. Hamilton concluded in 2000 the claims made by his detractors in the so-called "Burt Affair" had been either wrong or grossly exaggerated. Other scholars, notably
Leon Kamin, still accuse Burt of fraud. However, Burt's groundbreaking conclusions about the heritability of intelligence have been reproduced in numerous independent studies and are today generally accepted though some modern research indicates that the effect of heredity on intelligence is even larger than Burt originally proposed.