Twenty-four more years

In a previous post, I mentioned that I had once compiled data on education, occupation, and vote in American presidential elections from 1936 to 1992, using a combination of Gallup polls (1936-68) and the GSS (1968-92).  I showed changes in the relationship between college education and major party presidential vote.  I have finally gotten around to updating this with the GSS data through 2016.  Here is the estimated effect of college education (0=no college; 1=some college; 2=college degree) on Democratic vs. Republican voting among non-blacks, 1936-2016.

There is some variation from one election to the next--the pro-Democratic effect in 2016 election was higher than expected, but the most exceptional election was 1972, which set a record that was not broken until 2016.  However, the dominant thing is a trend that seems to have started at the beginning (the correlation with a time trend is about .85).  I would have guessed that the trend began or at least accelerated in the 1960s, but there's no sign of that.  That is, the relative shift of educated people towards the Democrats is a gradual process that was underway long before people started noticing it, and shows no signs of stopping. 

How big are the effects?  If you fit a linear trend for the education effect to smooth out the short-term variations, in an election where 50% of high school graduates voted Democratic, the predicted Democratic vote among college graduates goes from 34% in 1936 to 61% in 2016. 

The numbers above are not a contrast with all people without college education--they control for the changing effects of primary/secondary education (no formal education, elementary, grades 7-8, attended high school, high school diploma).  Those estimates are shown in the next figure.  Note that they are consistently in a pro-Republican direction, and have become more pro-Republican since the 1960s.  (This might be because the people with less than a high school diploma are increasingly likely to be immigrants, who tend to vote Democratic).

 

So what needs to be explained is apparently not a change in the effects of education, but a change in the effects of higher education.  Why has this happened?  In a paper published in 2002, I offered an idea: "growth in affluence and the division of labor has produced occupational niches for educated people who are critical of the status quo."  Previously, people might have developed "radical" ideas in college, but tended to abandon them after they had to earn a living.  Now, such people can find occupations where their ideas are accepted or even dominant.   I don't know if my explanation is the whole story, or even part of the story, but I was at least looking in the right direction:  the change in the effect of higher education seems to be a gradual shift, not closely tied to specific political events.

[Data from the Roper Center for Public Opinion Research and the General Social Survey]