[thephyber]

> ~50% of the bottom 20% has a college degree

I don't see "has a college degree" in the data. I think you are projecting it on the data.

It's more aptly described as "any college courses" and it's likely self-reported. Remember that the vast majority of "college" is not postgraduate degrees at elite Ivy League universities, but rather started (but didn't finish) at a community college or for-profit diploma mill.

I can easily imagine {teachers, college students, temporarily unemployed/underemployed taking care of dependents, retired persons} falling in the "college" + "bottom 20%" category.

[Kalium]

There's data in there about educational attainment. It makes a clear distinction between bachelors-or-higher and anything below that. Associate's degrees or just a few courses without completing a program fall into the latter grouping.

But yes, you're right. It's not clear exactly what data is being graphed.