Meta-d-prime ($\mathrm{meta}\text{-}{d}^{\prime }$)

The first-order sensitivity index that, in a fitted signal detection theory model, would generate the observed confidence discrimination. Model assumptions and sampling uncertainty matter; raw confidence–accuracy association alone does not estimate it.^[ref]

A model-based comparison of meta-d-prime with first-order discrimination, often their ratio. Interpretation becomes unstable when the denominator is close to zero. Efficiency, metacognitive calibration and overall confidence are different quantities.