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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Mars effect | 2/3 | https://en.wikipedia.org/wiki/Mars_effect | reference | science, encyclopedia | 2026-05-05T09:22:41.924157+00:00 | kb-cron |
=== The Zelen test === In 1975 Paul Kurtz's journal The Humanist published an article on astrology criticizing Gauquelin, to which the latter and his wife Françoise responded. Then Professor Marvin Zelen, a statistician and associate of the recently founded Committee for the Scientific Investigation of Claims of the Paranormal (CSICOP, now known as the Committee for Skeptical Inquiry (CSI)), proposed in a 1976 article in the same periodical that, in order to eliminate any demographic anomaly, Gauquelin randomly pick 100 athletes from his data-set of 2,088 and check the birth/planet correlations of a sample of babies born at the same times and places in order to establish a control group, giving the base-rate (chance) expectation for comparison (The 100 random athletes later expanded into a subsample of 303 athletes). In April 1977 CSICOP researcher George O. Abell wrote to Kurtz stating that Zelen's test had come out in the Gauquelins' favour. The Gauquelins also performed the test that Professor Zelen had proposed and carried out and found that the chance Mars-in-key-sector expectation for the general population (i.e., non-champions) was about 17%, significantly less than the 22% observed for athletic champions. However the subsequent article by Zelen, Abell and Kurtz did not clearly state this outcome but rather questioned the original data. In a rebuttal of the Gauquelins' published conclusion, Marvin Zelen analysed the composition, not of the 17,000 non-champions of the control group, but of the 303 champions, splitting this secondary subsample (which was already nearly too small to test 22% vs 17%) by eliminating female athletes, a subgroup that gave the results most favourable to Gauquelin, and dividing the remaining athletes into city/rural sections and Parisian/non-Parisian sections. Before and after publication of Zelen's results astronomer and charter CSICOP member Dennis Rawlins, the CSICOP Council's only astronomer at the time, repeatedly objected to the procedure and to CSICOP's subsequent reporting of it. Rawlins privately urged that the Gauquelins' results were valid and the “Zelen test” could only uphold this and that Zelen had diverted from the original purpose of the control test, which was to check the base rate of births with Mars in the "key" sectors. It appeared to him that the test had minimised the significance of the Mars/key-sector correlations with athletes by splitting the sample of athletes and that the experimenters, who were supposed to be upholding scientific standards, were actually distorting and manipulating evidence to conceal the result of an ill-considered test. The Kurtz-Zelen-Abell analysis had split the sample primarily to examine the randomness of the 303 selected champions, the non-randomness of which Rawlins demonstrated in 1975 and 1977. Zelen's 1976 "Challenge to Gauquelin" had stated: "We now have an objective way for unambiguous corroboration or disconfirmation ... to settle this question", whereas this aim was now disputed. Rawlins made procedural objections, stating; "... we find an inverse correlation between size and deviation in the Mars-athletes subsamples (that is, the smaller the subsample, the larger the success) – which is what one would expect if bias had infected the blocking off of the sizes of the subsamples". CSICOP also contended, after reviewing the results, that the Gauquelins had not chosen randomly. They had had difficulty finding sufficient same-week and same-village births to compare with champions born in rural areas and so had chosen only champions born in larger cities. The Gauquelins' original total list of about 2,088 champions had included 42 Parisians and their subsample of 303 athletes also included 42 Parisians. Further, Paris is divided into 20 arrondissements, different economic classes and ethnic groups typically inhabiting different arrondissements. The Gauquelins had compared the 42 Parisian champions (who had been born throughout Paris) to non-champions of only one arrondissement. If the 22% correlation was an artifact partly based on factors such as rural recordkeeping, economic, class or ethnic differences in birth patterns, this fact would be blurred by this non-random selection.
=== U.S. athletes – CSICOP === At the same time CSICOP began a study of U.S. athletes in consultation with Zelen, Abell and Rawlins. The results, published in 1979 showed a negative result. Gauquelin contended the KZA group demonstrated an overall preference for mediocre athletes and ignored his criteria of eminence and that they included basketball players and people born after 1950.
=== CFEPP test === In 1994 the results of a major study undertaken by the Committee for the Study of Paranormal Phenomena (Comité pour l’Étude des Phénomènes Paranormaux, or CFEPP) in France found no evidence whatsoever of a "Mars Effect" in the births of athletes. The study had been proposed in 1982 and the committee had agreed in advance to use the protocol upon which Gauquelin insisted. The CFEPP report was “leaked” to the Dutch newspaper Trouw. In 1990 the CFEPP had issued a preliminary report on the study, which used 1,066 French sports champions, giving full data for the 1,066 as well as the names of 373 who fit the criteria but for whom birth times were unavailable, discussing methodology and listing data-selection criteria. In 1996 the report, with a commentary by J. W. Nienhuys and several letters from Gauquelin to the committee, was published in book form as The Mars Effect – A French Test of Over 1,000 Sports Champions. The CFEPP stated that its experiment showed no effect and concluded that the effect was attributable to bias in Gauquelin's data selection, pointing to the suggestions made by Gauquelin to the committee for changes in their list of athletes. The CFEPP report was criticized by Suitbert Ertel on similar grounds as the American study – for including too many mediocre athletes – and also for using a too high chance-expectancy level. According to Ertel, a Mars effect could be detected by dividing the athletes into groups of eminence grading.