[jjk166]

That's not what they're doing here. They're asking the students how confident they are that they got what they think they got. Doesn't matter what the C group actually got, or what they think they got, they are still more confident that what they think they got was what they actually got than the B group, while the A group was less confident than the B group.

[adobkin]

To be honest, I misunderstood the study when I first ready it. However, the study is also not saying what you're saying. The authors had a bunch of students take a test and also predict their own score on it, as well as how confident that they were about their prediction.

The study says "for low performers, the less calibrated their self-estimates were the more confident they were in their accuracy". By "calibrated" the authors mean that the actual and predicted scores were the same. In other words, the C and D students were very confident that they got A and Bs.

The authors go on to explain:

"In other words, [for low performers] the higher the discrepancy between estimated score and actual scores, the greater participants’ confidence that their estimated scores were close to their actual scores... As expected, high performers showed the opposite pattern. High levels of miscalibration predicted a decreased in SOJ [second-order judgment]..."

Suppose everyone in the class was a B student and knew it. After taking the class, most got Bs but a few got A and a few got Cs and Ds.

Focusing exclusively on the D students (low performers), we find that they all expected to get a B. For these low performing students, the more miscalibrated they were the more confident they were. This makes sense because they expected to get a B and didn't expect to get a C or D.

Now let's take a look at A students. It makes sense that the more miscalibrated they are, the less confident they are because they all expected to get a B.