It’s not dubious at all. It’s a typology. They survey people on a bunch of questions, then break out the bundles of opinion. Very data driven. I agree that Bernie’s potential constituency is larger. At any rate, here are the categories:
Progressive Left
Establishment Democrats
Outsider Left
Stressed Sideliners
Ambivalent Right
Populist Right
Committed Conservatives
Flag and Faith Conservatives
And here is the quiz if you want to find out what bin you are in:
I’m going to make a thread where we can take the quiz in a moment.