"One Metric to Rule Them All": A Common Metric for Symptoms of Depression and Generalized Anxiety in Adolescent Samples

There is a significant degree of heterogeneity in scales that purport to measure depression and generalized anxiety in adolescent samples, which makes it difficult to directly compare scores across studies. The aim of the current study is to develop a common metric that facilitates the comparison of scores from different but related scales of depression and generalized anxiety using a large adolescent sample. A nonequivalent-anchor-test design in conjunction with simultaneous calibration was used to equate and develop a common metric for six different scales. The common metric provided scores with acceptable levels of precision across the -1 to 3 range on theta, which represents the more severe and often clinical end of the spectrum. Thus, in the current study, we identified a coherent common metric that is closely aligned with the "distress" subfactor of the Hierarchical Taxonomy of Psychopathology model. Additional validation testing in independent samples is now required.