The latest U.S. News Best Colleges rankings came out yesterday, but U.S. News rankings, it turns out, are something of a year-round industry. The number of U.S. News lists is vast (starting with “national universities,” “national liberal arts colleges,” going to “regional universities” and “regional colleges,” and including “top public schools,” and “historically black colleges and universities,” etc.) There’s something for everyone.

I discovered a most unusual U.S. News ranking thanks to an Education Trust tweet. The mission of Education Trust is “closing the achievement gap,” and it singled out the U.S. News headline as worthy of the Onion: Measuring Colleges’ Success Graduating Higher-Income Students.

Indeed, one wonders, what is the point? Why would we want to know if higher-income students graduate at rates different from the average student?

I still haven’t quite figured it out, but the ranking was presented and discussed in Robert Morse’s January 2014 column. (Morse is the U.S. News Best Colleges editor.) Schools are ranked by their graduation rates for higher-income students (defined as students who don’t receive Pell grants or subsidized Stafford loans). If those rates are the same or close to the graduation rates as a whole, then the school gets a high ranking.

I guess the point is that some people want to know what the “real” graduation rate of a school is—that is, without the “taint” of low-income students, who presumably lower the graduation rate. Or maybe they want to find out which schools treat higher-income students better than lower-income ones, as evidenced by graduation success.

So we have top performers like Stanford and Wellesley, where the graduation rates of the higher-income group are exactly the same as the rates of the school as a whole. (So they are serving lower-income students well? Is that the point?)

Then there are “overperforming schools” such as Wayne State and Hollins, where higher-income students graduate at a rate greater than the overall average. (Does that mean that lower-income students are bringing down the average and thus perhaps being discriminated against?)

And then there are “underperforming” schools, where the higher-income students are not graduating at a rate as high as the average student. (Could those be the party schools?)

If you understand the importance of this listing, please tell me.