Comment on Gignac and Zajenkowski, “The Dunning-Kruger effect is (mostly) a statistical artefact: Valid approaches to testing the hypothesis with individual differences data”

Gignac and Zajenkowski (2020) find that “the degree to which people mispredicted their objectively measured intelligence was equal across the whole spectrum of intelligence”. This Comment shows finding homoscedasticity is likely result a recoding choice by experimenters does not in fact indicate Dunning-Kruger Effect mere statistical artifact. Specifically, recoded test subjects' responses question regarding self-assessed comparative IQ onto linear scale when normal would have been more appropriate. More generally, researchers studying should be aware potential measurement problems may arise transforming an ordinal interval scale.