Unbelievably, the Battleground poll--sponsored by Georgetown University and conducted by two fairly well known partisan pollsters--is not weighted by education and comes in at ... 63 percent with a college degree. Holy cow. https://politics.georgetown.edu/battleground-poll/august-2020/

Interestingly, they posted the microdata for this poll, so that let's us dive in, see what's going on, and reweight.

Before we reweight, one initial question is how to make sense of their education question. In particular, should we include people with a two-year degree in our 'college grad' category.

Notice that these options don't actually correspond to the what the interviewer says. The interviewer asks for the highest level of education, and the interviewer then codes it in the right spot. Have they been instructed to code a two-year degree as 'some col' or a college grad?

No right interpretation. The norm is two-year separately but the literal interpretation combines them. And the huge postgrad number makes either interpretation possible (if there were *way* more colgrads than postgrad, then clearly two year included, right?)

And many of you have noted in the replies that the parenthetical note on years of education may help clarify to the interviewer that the two-year degrees belong in the some college category.

But we'll try it both ways. If we use *their* weighted figures for race, age, region, gender and *our* targets for education, then here's what you get:
With two-year as 'college grad': Biden+9, 52-43
With two-year as 'some college': Biden+6, 50-44

On closer examination though, one thing that's clear is that this poll is pretty different from our estimates across a number of different variables. Non-Hispanic whites represent 76% of RVs who offer a race/ethnicity! Both seniors (20%) and 18-29 year olds (9%) too low

If we take our weights across all five of these categories:
With two-year as 'college grad': Biden+10, 52-42
With two-year as 'some college': Biden+8, 51-43

One interesting thing here is the effect all this has on the crosstabs, too.
In *their* version, here's the result by race:
White: Biden 49, Trump 46
Black: Biden 82, Trump 13
Hispanic: Biden 59, Trump 25

In our version (Biden+8, assuming two-year = somecol):
White: Trump 51, Biden 44
Black: Biden 88, Tump 9
Hispanic: Biden 64, Trump 21
So you can see the often overlooked effect of not weighting by education on your nonwhite sample, too

This basic pattern helps explain some common patterns we've seen in state polling, where the polls that aren't weighted by education still seem to kinda fair ok or even underestimate Dems in the diverse southwestern states, even while understating Dems badly in the Midwest

Thus, our last adjustment: race by education. As you can see, having the right number of college grads is good, but having the right number of whites with a degree v. nonwhites with a degree is better.

This won't usually have a huge effect, but here it's worth a point.
If we take our previous Biden+8 (assuming two-year = "some college", but using our weighting targets) and now weight by race x edu as well, we now move to Biden+9, 51 to 43.

There are any number of other things one could conceivably weight for--density, marriage, and so on. I'm not going to go through all that. But I think this gives you a general sense of what's going on here, and the consequences of some of these choices.