No quarter, part 2

 In my last post, I discussed the idea that the combination of social liberalism and economic conservatism (or what is sometimes called "libertarianism") is an "empty quarter".   Of course, it's not literally true, but could the combination be underrepresented in some sense?  The figure below shows a hypothetical distribution of economic and social opinions.  I start by assuming a uniform distribution for both (which makes it easier to see the pattern in the picture), and then omitting everyone with an economic conservative/social liberal combination: 

The result is that the variance of opinions on social issues is larger among economic liberals than among economic conservatives, and the variance of opinions on economic issues is larger among social conservatives than among social liberals.  In my example from last time, I used abortion as the social issue.  The question had only two options, so the variance is just a function of the mean.  But the economic issue (redistribution) is on a scale of 1-7, so the variance is meaningful.  That is, the "empty quarter" hypothesis says that the variance in economic opinions will be larger for people who say that abortion should not be legal.  A comparison of standard deviations in three periods:

                           Legal      Not legal

1978-98             1.96           1.96
2000-2010         1.97           1.98
2012-2021         1.95           2.09

They are virtually the same in the first two periods, but there is some difference in recent years.  I tried a few more "social issues":  whether marijuana should be legal, whether sex between two adults of the same sex is morally wrong, whether there should be laws against the distribution of pornography to adults, and whether the Supreme Court had been wrong to rule against school prayer, using the same three periods for each.  In thirteen of the fifteen comparisons, the standard deviation of opinions on redistribution was larger among people who took the conservative position on the social issue.  The difference also seemed to become larger in the third period.  

I'm not sure that these results would hold up if you controlled for other potentially relevant factors (especially education).  I also haven't tried to translate the differences in standard deviation into an estimate of the degree to which the "libertarian" quarter is underrepresented, but I think that it's small.  Nevertheless, the results suggest there may be something to the "empty quarter" hypothesis, particularly in recent years.  Recent political history seems consistent with the idea that the economic conservative/social liberal combination is weakening.  Up until about ten years ago, quite a few people saw it as the wave of the future, but it seems to have faded in recent years, with some erstwhile libertarians shifting toward the "populist" right.  

If I had world enough and time, I would investigate this further, but I don't, so I'll just note it as a possibility.