DSM-IV internal construct validity: When a taxonomy meets data

The use of DSM-IV based questionnaires in child psychopathology is on the i ncrease. The internal construct validity of a DSM-IV based model of ADHD, C D, ODD, Generalised Anxiety, and Depression was investigated in 11 samples by confirmatory factor analysis. The factorial structure of these syndrome dimensions was supported by the data. However, the model did not meet absol ute standards of good model fit. Two sources of error are discussed in deta il: multidimensionality of syndrome scales, and the presence of many sympto ms that are diagnostically ambiguous with regard to the targeted syndrome d imension. It is argued that measurement precision may be increased by more careful operationalisation of the symptoms in the questionnaire. Additional approaches towards improved conceptualisation of DSM-IV are briefly discus sed. A sharper DSM-IV model may improve the accuracy of inferences based on scale scores and provide more precise research findings with regard to rel ations with variables external to the taxonomy.