Does astrology work? No, according to a detailed assessment of 152 astrologers that found their predictions were not only no better than random guessing, but also rarely agreed with each other.
There is no scientific basis for astrology, the belief that the motion of the planets and stars influences or predicts human behaviour, but it remains popular 鈥� one recent survey found that .
With previous scientific tests failing to dent astrology鈥檚 appeal, at US social enterprise came up with a new approach to help settle the question of its efficacy.
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鈥淲e asked, can we design a study where if astrology works, it鈥檚 very likely to come out in favour of astrology, and if it really doesn鈥檛 work, it鈥檚 likely that it鈥檚 going to come out against astrology,鈥� says Greenberg.
To do this, he and his colleague Andr茅 Ferretti asked six astrologers what they would want to know about a person鈥檚 life and character to accurately identify their birth chart. These charts are a common tool in astrology, constructed using the observed positions of celestial bodies at the time of a person鈥檚 birth, and claim to offer insights about that person鈥檚 character or life.
Using this advice, the pair developed a questionnaire to gather this information and selected 12 respondents whose answers would be used as part of a test, . They then recruited 152 astrologers to match each completed questionnaire to a birth chart from a choice of five. Each astrologer did this for every respondent, for a maximum possible score of 12.
When the , the average number of correct answers was 2.49, equivalent to what would be achieved by randomly guessing. 鈥淚t鈥檚 indistinguishable from random chance,鈥� says Greenberg.
Despite this, the astrologers had generally been confident in their answers, with 51 per cent thinking they had got six or more correct. 鈥淭hat is actually really key to our experiment,鈥� says Greenberg. 鈥淚t shows that the people that participated largely believed that they could do this task.鈥�
What is more, the astrologers rarely agreed with each other鈥檚 picks, and even the most experienced had agreement rates of less than 30 per cent. 鈥淭his, to me, was really surprising,鈥� says Greenberg. 鈥淚t suggests that astrology is maybe less standardised than you might think.鈥�
at the University of Hertfordshire, UK, says the work builds on a long history of similar research, but he doesn鈥檛 think it is likely to affect the decision-making of people who seek astrological advice. 鈥淕enerally, people engage with astrology because it addresses some kind of need,鈥� he says. 鈥淭o change their mind, you would have to address what got them to that point to begin with.鈥�
, a historian of astrology at the University of Wales Trinity Saint David, UK, says that while this study is an effective test of birth chart predictions, that doesn鈥檛 account for all forms of the practice. 鈥淭here is no one single method of astrology,鈥� he says, 鈥渨hich suggests to me that it is very difficult to take an objective view of what astrology is or what it claims.鈥�
