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Well, actually it's thirty-one point seven percent, if you don't round up

John Sides has a Monkey Cage post called Democrats are gay, Republicans are rich: Our stereotypes of political parties are amazingly wrong, which is really just a precis of an as-yet unpublished article by Douglas J. Ahler and Gaurav Sood called The Parties in Our Heads: Misperceptions About Party Composition and Their Consequences. (I should say that Matt Yglesias wrote about it over at Vox a month ago, but I don’t generally read his stuff these days.) Mr. Sides starts his note thusly: Here’s a quiz question for you: What percentage of Democrats identify as gay, lesbian or bisexual? Here’s another: What percentage of Republicans make more than $250,000 a year? I’d love to know what numbers Gentle Readers would guess for those two questions, ideally before reading the rest of this note.

My guesses were that 2% of Democrats so identified, and perhaps 10% of Republicans were over that mark. I had very little confidence in my numbers, but that was what I came up with off the top of my head. The actual numbers according to the article tell us that 6.3% of Democrats are LGB (the article sometimes includes T and sometimes not, which is bad and wrong but probably doesn’t shift the numbers much) and that only 2% of Republicans have quarter-million-dollar paychecks. I wouldn’t be altogether surprised if people in general under-stereotype their own party and over-stereotype the other, although the research appears to show that in general people over-stereotype both. Still and all, for my over-stereotyping of the Other Party, considering that (according to the table on p. 46) 90.9% of respondents overestimated the correct answer, and (according to the terrific plots on pp. 47-48, if I’m reading them right) 75% of Republicans estimated the percentage of “rich” Republicans as 20% or more, I think it wasn’t a bad guess.

My main complaint, though, is about the use of averages in both the paper and the Monkey Cage post. Some Gentle Readers will remember how much I loathe the use of averages when you don’t mean to average things, and in particular, I hate attempts to average people. Mr. Sides says “On average, Americans thought that 32 percent of Democrats are gay, lesbian or bisexual.” In the paper’s abstract, Mr. Ahler and Mr. Sood write that “people think that 32% of Democrats are LGBT”. There are graphs and tables that similarly use the average—sometimes with a confidence interval. I find the highlighting of this average number as utterly and completely perplexing. What difference would it make in the study if that number were 30? Or 35? Or 40? What’s important is that they were overestimating, and overestimating by a lot—highlighting the average just gives a totally false sense of confidence that people really put that 32 number down, which of course most of them do not. It also makes that number seem important, which, again, it is not. What is important is that people consistently overestimate the extent to which the Parties are demographically different from each other, and different from the country at large. The 32% average of estimates of LGB Democrats is meaningless, as is the 38% average of estimates of $.25M/yr Republicans. I believe these numbers convey less than thirty-or-more would. That’s why the graphs are so good—here, I’ll reproduce them (this is smashed together from the two graphs).

The plots display the full range of perceptions reported (the thin teal lines), the interquartile range of perceptions (the thick teal section), and the median with a 95% confidence interval (the white band and notch in the middle of the IQR). They also display the population estimate of PR(group|party), depicted as vertical red lines with gray 95% confidence intervals based on sampling error.

Now, I know you can’t use those graphs in an abstract or the lede to a blog post, but that doesn’t mean you should use averages.

Tolerabimus quod tolerare debemus,


Huh: I feel like I'd be more interested in "what percent of people making more than $250K are Republicans" than in "what percent of Republicans make more than $250K". Or maybe in both of those things, but I feel what I want to know isn't so much "are all Democrats gay", and more like "are all gay people Democrats". If 2% or 30% of Democrats or gay, that doesn't tell me as much about which Party is supportive of gay people as if 100% of gay people are Democrats, does it? (Among other things, if I don't know what percentage of the total population identifies as gay, I don't have any idea whether 2% or 30% is high.)

Your analysis is not wrong, but it's not really how people come to support political positions.

The issue is, at heart, that people think ‘Democrats are like this, but Republicans are like that’ in much the same way that they think ‘English majors are like this, but Chem majors are like that’. Or ‘San Franciscans are like this, but Angelenos are like that’. Or even ‘People who watch the Simpsons are like this, but people who watch the Kardashians are like that’. And that image of what the party members are like has a huge effect on what people think of the policies those parties support.

Much of politics is tribal, and even though most of us think that we support individual politicians because we agree with their individual policy preferences, in fact we support policies largely because we identify with groups. Now, you may think that's illogical and dangerous, but it's how the mind works. And this study is pointing out that we identify with (and against) groups due to a completely incorrect picture of what those groups are like.


I should add—it's not like I think it's impossible to come to a policy preference independently or through weighing evidence, it's just time-consuming and resource-intensive, and nobody can do it for every possible policy. Most people don't have time to do that sort of thing for very many areas, and since tribal affiliation actually works quite well as a hermeneutic, it all works out OK.


I buy your argument there, I'm just not sure about the stats part. If every gay person I know is a Democrat, doesn't that make me likely to think "gay people" when I hear "Democrats"? It doesn't matter whether those gay people are 3% of of the party or 33%: If I can't imagine a gay person in the Republican Party, that leads me to say "Republicans generally aren't gay", and vice versa.

I dunno, maybe not, or maybe not for most people.

Oh, also, that previous comment was me, because I am forgetful.

Back a few years ago, I was hocking about how the Other Party had hung the frame on My Party that we hate the Bible—people knew (more or less accurately) that most atheists were Ds and assumed that most Ds were atheists. This did My Party no good at all (in addition to being, you know, false).

If, f’r’ex, a person thinks ‘The Democrats are all gay, and I'm not gay, so I am not a Democrat’ and ‘the Republicans are all rich, and I'm not rich, so I am not a Republican’... you get a lot of tribal independents, which doesn’t do the system any good.

I don't know that there’s anything much to be done about it, in the sense of, I dunno, educating people about the actual demographic make-up of the Parties (both are mostly white middle-class Christians, of course). But it’s information worth keeping in mind as various of us go about the process of persuasion.

And of course I’m mostly just cranky about the use of averages, aren’t I?


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