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Ertel's Appraisal of Shawn Carlson’s Renowned Astrology Tests
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Vernon Clark's Blind Tests
1959-1970
Between 1959 and 1970, US psychologist Vernon Clark performed a series of blind matching tests involving a total of 50 professional astrologers. While a control group of 20 psychologists and social workers matched 10 pairs of charts with professions to a level of 50% as expected by chance, the astrologers successfully matched 65%. (Clark 1961) Though this result may not sound significant, the odds of this being a chance event is 1 in one in ten thousand. (p=0.0001)
In a later study, Clark removed any possible cues from self-attribution from knowing sun sign traits, by using matched pairs with the same sun sign. The astrologers matched charts to case histories 72% of the time. An even more significant result. (p=.00001)
In the final experiment, 59% astrologers were able to distinguish between an individual with a high IQ and one with cerebral palsy. Even this lower result was significant (p=.002). Overall out of 700 judgements the astrologers matched correctly 64% of the time. (p=0.00000000000005 or 5 in 10 trillion). (Clark 1970)
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