We examine the extent to which unions deemed more favorable appear more frequently than expected by chance. Put simply, if an individual is exposed to a marriage market consisting of 50% of individuals who are type “favorable match” and the other 50% being type “unfavorable match,” the probability of marrying an individual belonging to either category simply by chance is 50%. If, however, preferences and compatibilities consistent with the hypotheses tested in this paper exist, the probability of marriage to an individual belonging to the “favorable match” category would exceed 50%. Consequently, if the actual number of “favorable” unions statistically significantly exceeds what would be expected had the process been driven solely by chance (or some other characteristic not correlated with the zodiac sign), this would support the hypotheses tested in the paper. More specifically, this would be consistent with a higher degree of compatibility among astrologically favorable couples, reflected in an elevated share among the observed marital unions. We approximate the marriage market population through the distribution across zodiac signs of the population of index individuals, and differences in means between the predicted and actual number of marriages are assessed using t tests.
Apart from the key independent variables for the article, measuring the zodiac sign combination of the couple, the main models only control for the sex of the index person as well as their nativity
The second part of the analysis is represented by the estimation of Cox proportional hazards models. Here, we examine whether astrologically favorable couples are less likely to divorce. The union represents the unit of analysis at risk of dissolution through a legal divorce from the time of marriage. Time at risk is specified as the number of days elapsed from marriage and unions are followed until legally divorcing or censoring. The motivation for this is that the majority of the standard control variables in an analysis of divorce can be argued to be simultaneously affected by the individual’s zodiac sign, thus making them bad controls. For the sake of being able to compare the size of the associations between zodiac-combinations and the risk of divorce with the influence of other characteristics that are known to be important, such as educational attainment and the age difference between the spouses, we also estimate models including a full set of spousal sociodemographic characteristics. In addition to already mentioned determinants, the complete models also control for whether the individual and their spouse were native born, the highest (observed) marriage order of the current union, and whether either spouse important source has any children under the age of 18. The sample means of the population examined in the multivariate analysis are presented in Table A1, Additional file 1.
We begin the analysis by examining the extent to which astrologically favorable relationships are overrepresented among the 66,063 unions that are observed in the data, translating to an average of 458.8 unions for each of the 144 unique zodiac sign combinations. As previously mentioned, we expect the distribution of the index individuals to approximate the marriage market population, implying that-in the absence of any preferences that correlate with zodiac sign-an individual’s probability of marrying someone who, e.g., happens to be Pisces should amount to 8.7% (,063), unconditional on the index person’s own sign. As displayed in Table 2, the share of index individuals who have a spouse who is a Pisces ranges from a low among the Aquarius of 8.05 percent, to a high of 9.25% among index individuals belonging to the zodiac sign Cancer. As an initial test of the validity of the astrological predictions presented earlier, evidence in favor of the examined classifications is obtained if an overrepresentation similar to the Cancer-Pisces characterize zodiac sign combinations that are considered to be astrologically favorable. Within each category of compatibility, we compare the mean number of observed to expected unions across all zodiac sign combinations, using t tests to examine whether the difference is statistically significant, consistently finding this not to be the case (p > 0.1).