Cross-measure Equivalence and Communicability in the Assessment of Depression: a Fine-grained Focus on Factor-based Scales

Depression is heterogeneous, however, depression measures conceptualize it as homogeneous. To help fulfill NIMH's strategic plan to focus on components of depression, this study analyzed the psychometrics of factor-based subscales in the BDI-II, CES-D, IDAS, and IDS. CCA was also used to explore redundancy across measures. Using a diverse sample of symptomatic undergraduates, this study found the IDAS to be the best measure, with complete DSM-IV symptom coverage and psychometrically sound subscales. The other measures did not have consistent subscales or coverage of symptoms. Furthermore, CCA revealed low levels of redundancy across measures. These results serve to disabuse the field of a perception that different measures of equivalently measure depression. Conversion tables were provided to empirically compare scores from different measures