Homogeneity of Beck's Depression Inventory (BDI): applying Rasch analysis in conceptual exploration.

Rasch analysis of the BDI resulted in three unidimensional subscales, viz. a "Mood and Inhibition", a "Guilt and Failure" and a "Somatic" subscale. All three subscales were of moderate to good internal consistency, and intercorrelated modestly. No significant correlations with sex, age, or education were found. It can be concluded, that the BDI does not, in terms of Rasch measurement model, constitute a unidimensional scale for the measurement of depression.