This past season/month/week, there has been a lot of talk about whether Donald Trump has been “graded on a curve” during this presidential campaign. Indeed, CNN’s Reliable Sources had a  segment on this point over the weekend. Anytime a metaphor is beaten into the ground, my Washington Post colleague Carlos Lozada gets fidgety. So I suspect that segment led him to tweet the following:

Challenge accepted! What is grading on a curve, and is that what the media is doing to Trump?

As I have always understood the term — and other profs’ mileage may vary — “grading on a curve” means that you adjust students’ raw numerical grades in a course so that they conform to a preconceived distribution. This means that only a certain percentage of the class will receive “A” grades, a certain percentage “B” grades, and so forth.

Now there are two reasons to grade on a curve at modern universities. The first — common in the sciences — is if the course material is so hard that an alarming fraction of students would fail if one stuck to a strict numerical score of anything below 65 percent being a “F.” Indeed, as this Hamilton College biology professor’s explainer makes clear, that’s why she grades on a curve.

The second — way less common, but when it happens often occurs in the humanities — is if the students are such overachievers that too many of them would earn “A” grades. In a world of grade inflation, a tough university grader wields a disproportionate influence over things such as class rank, because their course is the rare one that has a wide distribution of grades.

[Do you grade on a curve?–ed. No. I grade graduate students mostly, and the meaning and distribution of grad school grades are somewhat different from those in undergraduate courses. So how would you grade me as an editor?!–ed. Incisive and powerful! Proceed—ed.]

Curving grades makes sense in particular contexts, but there’s always an underlying assumption being made when one does it. As Hamilton College professor S.A. Miller explains:

The basis of the practice derives from assumptions about statistical distributions of scores (bell curve). If you assume that scores should fit a normal curve, then it makes sense to “normalize” them so they fit under a normal curve. Normalization also requires that overly high scores be adjusted downward for conformity. Either way, data are distorted and some information is lost.

So, is the media grading Trump on a curve? Sort of.

In the CNN segment, the New York Times’ Mark Leibovich raised a trenchant point about the flaw in this metaphor:

No one agrees on the curve anymore. I mean, that’s the central problem.
The notion of a curve in, say, math, like in fourth-grade math, if this test is a greater than curve, there’s an objective number that you’re grading it. There’s absolutely nothing objective about the agreed upon, you know, whatever, I mean, agreed upon argument in our culture, that’s there’s one arbiter, whether it’s Walter Cronkite or Tim Russert or whoever, that can decide.

So that’s part of the problem — there might be instances in which the media thinks there is an objective standard and maybe there isn’t.

However, Leibovich went on to say something in the segment that suggests the existence of an implicit curve:

I do think that it is incumbent upon reporters to, when a blatant falsehood is spoken, to actually either parenthetically or just state it explicitly that this is just not true. But I also think that when you say, when [you] get into on one hand and on the other hand thing, and then make a judgment where you say, this is racist, this is white supremacy, you’re basically trying to overturn a judgment that’s been rendered by one of our two major parties, which is that person is acceptable to be their nominee of a party.

And we arrive at the way in which Trump, consciously or not, may be graded on a curve. The assumption in mainstream media coverage of a general-election campaign is that, in the 21st century, neither major party would nominate someone for president who espoused racist views or welcomed foreign espionage or demonstrated breathtaking ignorance on important policy questions. When Trump says egregious things, the media reports it in a perfectly straightforward manner. But there’s a default setting that there’s no way Trump actually believes the racist stuff, or that he’ll bone up on the policy stuff.

Grading Trump on a curve means it is assumed that as the GOP nominee, he will be up to the task of being president whether or not that is actually true. As a close Trump watcher for more than a year, I see no evidence that this is true. But when you read about Trump “maturing” as a candidate, or see news anchors discuss his myriad “pivots,” you see the curve at work. Because if there’s one thing the mainstream media cannot say explicitly, it is that the Republican Party willingly chose an ignorant bigot as its nominee.