+The surprising thing is, if you look at what trans women say to each other when the general public isn't looking, you see the same stories over
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+(examples from /r/MtF: ["I get horny when I do 'girl things'. Is this a fetish?"](https://www.reddit.com/r/MtF/comments/qy4ncb/i_get_horny_when_i_do_girl_things_is_this_a_fetish/), ["Is the 'body swap' fetish inherently pre-trans?"](https://www.reddit.com/r/MtF/comments/q8k57y/is_the_body_swap_fetish_inherently_pretrans/), ["Could it be a sex fantasy?"](https://www.reddit.com/r/MtF/comments/rd78kw/could_it_be_a_sex_fantasy/), _&c._, _ad infinitum_) over and over and over again.
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+After observing this kind of pattern in the world, it's a good idea to do surveys to get some numbers and data to help learn more about what's going on with the pattern. There's clearly a thing here, but is the thing being generated by a visible minority, or is it actually a majority? When [82% of /r/MtF users say Yes to "Did you have a gender/body swap/transformation "fetish" (or similar) before you realised you were trans?"](https://www.reddit.com/r/MtF/comments/89nw0w/did_you_have_a_genderbody_swaptransformation/), that makes me think it's a majority.
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+When you pose a superficially similar-sounding question to a different group, are you measuring the same real-world phenomenon in that other group? Maybe, but I think this is nonobvious.
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+And it contexts where it's not politically inconvenient for him, Scott Alexander agrees with me: he wrote about this methodological issue in ["My IRB Nightmare"](https://slatestarcodex.com/2017/08/29/my-irb-nightmare/), expressing skepticism about a screening test for bipolar disorder:
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+> You ask patients a bunch of things like "Do you ever feel really happy, then really sad?". If they say 'yes' to enough of these questions, you start to worry.
+>
+> Some psychiatrists love this test. I hate it. Patients will say "Yes, that absolutely describes me!" and someone will diagnose them with bipolar disorder. Then if you ask what they meant, they'd say something like "Once my local football team made it to the Super Bowl and I was really happy, but then they lost and I was really sad." I don't even want to tell you how many people get diagnosed bipolar because of stuff like this.
+>