Accuracy and stability of metacognitive monitoring: A new measure

An examination of gamma (?; Goodman & Kruskal, 1954) and the Hamann coefficient (HC; see Schraw, 1995) as a measure of feeling-of-knowing (FOK) accuracy in the prediction of subsequent memory performance shows that neither coefficient provides a pure measure of accuracy in 2 (feeling-of-not-knowing and FOK) × 2 (correct and incorrect recognition) cases. γ underestimated accuracy in the m × 2 case with m being an integer larger than 2, producing low and unstable values of γ. In the present study, FOK predictive accuracy is treated as the extent to which the percentage of correct recognition can be increased by an increase from one FOK rank to another. A statistic computing the relative magnitude of the percentage increase to its maximal increase, designated as C, is able to provide a correct estimate of accuracy. Furthermore, the value of C is stable across different portions of FOK data and is free from restricted-/truncated-range and fineness/ coarseness effects.