Although it was a giant leap forward when it was introduced, the classic approach to the norming of neuropsychological tests (Capitani, 1987) has two main limitations: (i) it doesn’t consider possible interactions between covariates (e.g., age and education); (ii) working on by–subject percentages of correct responses, it cannot consider item covariates (e.g., frequency, length, imageability) that are known to affect performance substantially. Here we show how to overcome these limitations, and how this improves our diagnosis.