The article shows that the qualitative claim, that low scoring people tend to overestimate, and high scoring people tend to underestimate their ability, is nothing but a statistical obviety.
For the Dunning-Kruger effect to have psychological significance, you must quantify this, and show that they overestimate their abilities more resp. less than expected.
Regardless of how you set your expectation/null hypothesis, the absence of the effect would mean that the lowest scoring quartile would on average estimate their abilities to lie at 50% or below. It is found however that people in the lowest scoring quartile position themselves in the third or fourth quartile.
I'm not saying that this is necessarily deep or unexpected, just that the article only shows that the qualitative statement is true regardless of any psychological factors, and not that the Dunning-Kruger effect doesn't exist
The y-axis is actual_score - self_assessed_score, right?
So we are interested in whether the average of this y-axis value differs between high scoring and low scoring groups. The study that shows there is no D-K effect [1] linked by the OP article shows there isn't a difference in the average value (y-axis) between groups. In fact the mean value was 0 for all quartiles. So we can conclude that we have found no systematatic over/under reporting of actual vs percieved skill. People in the lowest quartile do not appear to position themselves higher than they should. Or at least, we can't reject the null hypothesis
For the Dunning-Kruger effect to have psychological significance, you must quantify this, and show that they overestimate their abilities more resp. less than expected.
Regardless of how you set your expectation/null hypothesis, the absence of the effect would mean that the lowest scoring quartile would on average estimate their abilities to lie at 50% or below. It is found however that people in the lowest scoring quartile position themselves in the third or fourth quartile.
I'm not saying that this is necessarily deep or unexpected, just that the article only shows that the qualitative statement is true regardless of any psychological factors, and not that the Dunning-Kruger effect doesn't exist