The paper presents results with statistically significant p values. Does this mean the hypothesis is valid? Or has something else slipped in and created a small bias that produces this test result?
I noticed a few things:
1)VE-SA aspects (as defined in the paper) happen much more often in some years and are much more rare in other years. This chart shows the number of days with a VE-SA aspect by year for 1880-1920:
Periods of relatively high frequency of VE-SA aspects alternate with periods of much lower frequency. A person born between 1886-1894 (or 1903-1911) had about 30% more chance of having a VE-SA aspect than somebody who was born from 1895-1902. Could this affect the results in some way? We do know that France had a huge demographic shock in WWI, with millions dying and postponing marriage and/or child birth. See: http://economics.ucr.edu/seminars_colloquia/2013/economic_theory/Vandenbroucke%20%20corrected%20paper%20for%204%2015%2013%20seminar.pdf
This may have interfered with the changing frequency of VE-SA aspects in the portion of the population that was most hardly hit by WWI.
2)Gauquelin's hereditary data seem to have the birth data only for certain years and miss them almost completely for other years. This chart show the number child birth records in the collection by year:
There are 1660 birth records for 1913-14 and then almost none for 1915-18 (lost in war?). Then there are more than 3000 for 1919-20 and again almost none for 1921-22, followed by over 8000 for 1923-24. For 1929-30 there are more than 10000 births followed by less than 2000 in the next two years. This is clearly a very incomplete set of birth records that doesn't reflect the true demographic changes of those days. Doing astrological research on this set of child birth data is going to be fraught with problems. The paper uses birth of the first child as a proxy for the marriage date to test for marriage delays. This distribution of birth records makes it very unlikely that they are suitable to be used as a proxy for marriage date.
I communicated those concerns to the author of the paper, but he waved them away. Perhaps in astrology we do not doubt results as long as they support our theories? Anyway, the true test for any hypothesis is always in confirming it on other data collections. And those days plenty of marriage data can be pulled from the internet. I found an almost ready-to-use collection of marriage records, including birth dates as well as the marriage date, here: http://geneaknowhow.net/script/dewit/wezembeek-oppem-croon.htm and tested them for VE-SA aspects. Because the marriage dates are included we do not need to use birth of child as a proxy for marriage date. The results are available here as public google docs: spreadsheet1 and spreadsheet2.
The hypotheses are not confirmed. Persons with VE-SA aspects actually had a slightly smaller age difference and married a little bit quicker than average, but nothing statistically significant. Many more marriage records from Belgium can be pulled up here and here, but I will need to code a script to filter the data from them. That will be for another day.
I want to make sure I'm reading this right. The original data, while definitely spotty, consists of how many tens of thousands of charts? And the new data set you have introduced has 794? Is that correct? And therefore, the hypotheses are not confirmed? Am I reading that right?
ReplyDeleteHi,
ReplyDeleteYes you read that correctly. Testing with a smaller data set than the original study is OK. And 800 data covering 1600 persons is not that small a sample. Of course, with more data a result is always more reliable. Here the hypotheses are "not confirmed" by this test, because the outcomes are the opposite of what is expected based on the hypotheses. I would be lying if I wrote that the hypotheses were confirmed.
Please note that I am not writing that the original study is "invalidated" by this result, it isn't. But of course, if the hypotheses are being testing on more marriage data and they keep failing to confirm the results of the first study, then the hypotheses would become very weak. To become confident in a given hypothesis we want to see the results confirmed in several follow-up tests.
Certainly you want to keep adding more marriage data to the mix, because it can be used in any number of other studies. At the same time, I'm always cautious about comparing 'apples to oranges.' For example, what do we know about marriage customs in mid-18th century Wezeembeek? How much romantic attraction and personal choice were involved compared to marriages in mid-19th century Wezembeek, or to marriages in mid-20th century France? Are we really comparing the same thing at all?
ReplyDeleteAlso, if war had an impact on 20th century French marriages, which it surely did, what about Wezembeek? It's in Europe, where historically, there was often little peace to be had, so perhaps the community's involvement in any contemporary warfare needs to be factored into the marriage data somewhere?
A marriage is still a marriage. Even today, if we look at romantic attraction or personal choice, a marriage in Europe or US is very different from one in India or Iran.
DeleteYour comment is not unimportant however. In those days there was no divorce and a woman usually couldn't get married without the approval of the father. Of course, if the daughter was pregnant already the father would usually agree.
So, a man or a woman usually married only once, unless the wife (or husband) died early, then he could re-marry. WWI widowed millions of people, who then remarried after the war (not rarely to a much younger woman, who was more likely to take an older husband because there was a shortage of men).
We can see what this leads to in the original study. The Gauquelin data are mainly children born after 1918, with the birth dates of at least one of their parents. The data do not contain any persons that remained childless or remained single. The study assumes that birth of 1st child is a proxy for marriage date. What is not considered is that this may have been a 2nd marriage from one or two person who were widowed in the ware. Remarrying at a later age usually leads to bigger age differences between partners and what is being perceived as a "delayed marriage" in the study.
The people born after 1885 were not likely to be widowed by the war, because they were not likely to be married when the war started. So, for them we are probably seeing first marriages. But for the person born before 1885 we will be seeing a lot of second marriages, but we wouldn't know. We then interpret that as a late marriage, but that is a wrong assumption in a number of cases. So, this will distort the statistical results.
The data from Wezembeek are from before 1910, so not affected by WWI. Sure, there were wars and battles in the 19th century too, but they didn't cause the kind of demographic shock that WWI caused in France. This is probably the reason why we get a different result in this study. We will see what happens when we look at other data.