I have news. I finished the last two chapters of Probably Overthinking It last week and sent a complete draft of the book off for technical review. Yay!

In the last chapter, I used some methodology I thought was worth reporting, but too technical for the book, which is intended for an intelligent general audience. So I’ve started a public site for the book, where I will post technical details from each chapter and maybe some of the material that I decided to cut.

The last chapter is about changes in political beliefs over the last 50 years, particularly along the axis of liberal and conservative views. I found 15 questions in the General Social Survey (GSS) where liberals and conservatives give different answers by the widest margin. The following figure shows the topics, which will come as no surprise, and the differences between the groups.

Based on the answers to these questions, I estimate a score for each respondent that quantifies how conservative their beliefs are. By this measure, people have been getting more liberal, pretty consistently, for the last 50 years:

And it’s not just liberals becoming more liberal. People who consider themselves conservative are more liberal than they used to be, too.

That gray line is at 6.8 conservative responses, which was the expected level in 1974 among people who called themselves liberal.

Now, suppose you take a time machine back to 1974, find an average liberal, and bring them to the turn of the millennium. Based on their survey responses, they would be indistinguishable from the average moderate in 2000.

And if you bring them to 2021, their quaint 1970s liberalism would be almost as far to the right as the average conservative.

If you are curious about the methodology, here’s the article explaining where these results came from.

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