more details McGrew & McFall 1990


To assess whether the ability of professional astrologers to match birth data related to a person with a file including diverse information on the same person is greater than what would be expected by chance.  The astrologers decided what personal information was required to optimize results.

The astrologers /assessors

6 professional counseling astrologers were nominated by the Indiana Federation of Astrologers (IFA)  to be the assessors in the capacity of astrologers “with superior ability”, one man and five women.  The researchers added 1 control  assessor, a male graduate student in clinical psychology, to the group.

The test subjects

23  subjects (4 men and 19 women) 30-31 years old, recruited by putting an advertisement in the newspaper, offering vocational testing to native-born American adults.  They were told that accurate birth information was required because the purpose was to assess possible influences of the maternal diurnal cycle during the birth process that could have an impact on the later development of the neonate.  The cover story was devised to prevent bias due to the beliefs of test subjects on astrology.

The astrologers insisted that the subjects had to be at least 30 years of age, because younger subjects might not have fully developed the personality reflected by the natal astrological chart, and from very different walks of life.   The researchers kept the age range very narrow so that age would not be a factor that could be used for matching.

Birth information

Date, place and time of birth, based on birth certificate, hospital records or county records.  Accuracy was to be within 10 minutes.


Case File contents

The astrologers of IFA were asked to provide a list of the kinds of information they would require to match the birth dates to the personal case files.  Based on their response a  61-item questionnaire was drawn up called the Personal Characteristics and Life History Summary (PCLHS).  Its format was approved by IFA.

The material available to match the subjects was:

·        the filled-in PCLHS

·        Two photographs (full-face and profile) so that the astrologer could see the body type of the person

·        A computer-scored summary of two standardized psychological tests (the Strong-Campbell Interest Inventory – form T325 and the Cattell 16 P.F. – Form) to provide information on general interests, potential vocations and personality traits


The researchers edited the information provided to ensure that no key identifying items were included (this procedure required only minor editing in 4 cases) and then put all the information together in a case file identified with a code that corresponded to the last 4 digits of the volunteer’s social security number.

The astrologers and the control assessor received the 23 case files together with a separate list of 23 birth dates + place and time of birth, and an answer form.


Next to each birth date, the assessors were to enter the code number of the case file that was their first choice for a match, and their level of confidence (0-100%).  They could also indicate alternative choices if they wished.

The astrologers and the control subject worked independently and mailed the completed answer sheets to the researcher.


The correct matches ranged from 0 to 3(most frequent: 1); the control subject achieved 3 correct matches.  In other words, none of the assessors performed at a level that was significantly better than chance. 

Moreover, there was little relationship between the confidence in making the matches and their correctness.  When the second choice was included, correct matches increased only for two subjects.  In particular, the control subject increased the number of correct matches from three to four i.e. improving his performance to a greater level than the astrologers.

What is more, there was no consistency in the replies provided by the astrologers, whose replies appeared to be due to chance.  In other words, the astrologers failed to provide consistent judgements even though the astrologers purported to be using the same system and methods to make their predictions.

The authors of the paper came to the conclusion that “the astrologers probably could have done just as well if they had matched the birth information with the case materials in a random manner”


This study was performed more than 30 years ago.  Today I do not think that any astrologer would accept to participate in an investigation where fully reliable birth times are not provided.  In this study the birth time was based on a birth certificate or a hospital record.  Unless the reporter was interested in astrology and knew how important the accuracy of a birth time is up to approx. one (yes, one!) minute, the information on such documents is approximate and may have a negative impact on the quality of astrological predictions. A technique called rectification has been developed by astrologers, whereby they correct the birth time based on important life events, such as marriage etc.  The problem is that the technique is tedious and takes a long time, often the best part of a day, so funding should be available for the correction of each birth by a separate astrologer and the study would become expensive.

Another flaw is the age group – 30-31 year olds, as IFA members pointed out when the data were presented.  The astrologers had asked for test subjects aged at least 30 years, not just 30-year-olds.  I fully agree with the researchers that age could have been a confounding factor, but I would have selected, for instance, 70-71-year olds for which there would have been many life events available for the rectification process, which is more accurate when many events are available.   Moreover, there would have been the certainty that certain traits had manifested and that certain life events most likely had or had not happened, e.g. at 70 an unmarried and/or childless person is unlikely to marry or have children, whereas this cannot be said about a 30-year old; moreover, also the career and financial situation is clear, whereas at 30 the person may still be developing the qualities required for success. 

Finally, regarding the lack in consistency of the matching among astrologers, it should be borne in mind that there are many astrological techniques that could have been used for the matching, even if the type of astrology was the same (in this case presumably Western Astrology).  The researchers claim that the astrologers purported to use the same techniques, but nothing is specified in the paper, so we cannot rule out that the astrologers used personal techniques that differed and therefore resulted in different matches. 

For these reasons I believe that also this study is inconclusive.