Factor structure and normative data of the Beck Depression Inventory (BDI-II) in the general Peruvian population

The aim of this study was to analyze the dimensionality of BDI-II, as well as to demonstrate gender invariance and construct normative data in the general Peruvian population. For this purpose, the BDI-II was administered to 1665 participants (51.83% women) from different cities of Peru (75.92% from Cajamarca, 11.05% from Lima, 6.42% from La Libertad and 2.62% from Lambayeque), with an age range of 18 to 54 years (M = 24.99; SD = 8.73). Fourteen models, based on previous studies, were tested by confirmatory factor analysis. The results indicated that the bifactor and second-order models had convergence problems, whereas the two-dimensional and unifactor models had adequate goodness-of-fit indices. The unidimensional model was selected due to its theoretical coherence, since the BDI-II creators point out that the test should be interpreted globally by adding the 21 items, and discourage interpretations by calculating scores separated by dimensions. Furthermore, the antecedents indicate that the variance explained by the second factor is very low. Therefore, this approach would be unjustified. In addition, previous studies have indicated very high interfactor correlations. Finally, gender invariance was demonstrated, and normative data were calculated using percentiles, indicating that scores above 11 would be clinically relevant. In conclusion, the BDI-II has good psychometric properties in a unidimensional structure with 21 items, which is sex invariant and has adequate normative data for the general Peruvian population.