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Volume 11: Number 1: Article 1
Biased Data Selection in Mars Effect Research
Suitbert Ertel, Institut für Psychologie, Gosslerstr. 14, 37073
Göttingen, Germany
Kenneth Irving, 596 Villa Ave., Staten Island, NY 10302,
U.S.A.
An earlier study (Ertel, 1988) showed that original evidence for Gauquelin's
Mars effect with eminent athletes (Gauquelin and Gauqelin 1970) was
based on an incomplete data sample. When athletes initially discarded
by Gauquelin were included the Mars effe ct declined. The present study
bears on a more subtle effect of the same bias. Gauquelin's original
definition of planetary effects was based on birth frequences obtained
in a "narrow" zone of the planet's daily circle (G-sector zone). After
accumulating results over decades of research, he found that the area
just preceding his narrow zone indicated initial planetary effects;
he therefore proposed to include initial sectors in an "extended" G-sector
zone definition. Assuming that these initial G-sectors had been ignored
prior to 1984, the authors suspected that an unbiased proportion of
births for these sectors in Gauquelin's exempted data should contrast
with the biased proportion known to exist in the "narrow-zone" sectors.
This idea gave rise to a new bias detector (IMQ, initial vs. main sector
quotient), whose validity was confirmed with the biased Gauquelin data.
Selection bias for Gauquelin turned up in his athletes study only; the
IMQ did not indicate like anomalies for six other professional inve
stigations conducted by Gauquelin. The IMQ was also applied to three
athlete samples collected by skeptic organizations. Among them, the
CSICOP data for U.S. athletes revealed an anomalous IMQ similar to Gauquelin's
unpublished athletes. The results therefore suggest that a certain proport
ion of U.S. athletes with unwelcome positions might have been exempted
from analysis (p = 0.01). Support for this suspicion is provided
by complementary evidence indicating biased admissions of less eminent
athletes to the U.S. sample while the preference for most eminent athletes
was required. Thus an avoidance of G-sector cases, consistent with this
bent, cannot be disavowed. Nevertheless the authors refrain from firm
conclusions as this case is circumstantial. It is suggested to merely
disregard the CSICOP's negative result of their study in future discussions
of the Mars effect as long as appropriate steps to convincingly resolve
remaining ambiguities have not been not made.
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