You don't always get what you pay for: Measuring depression with short and simple versus long and sophisticated scales

In three studies subjects' depressiveness was assessed by a variety of instruments. Questionnaire scales were either comparatively short or long and either fairly simple, content oriented, and undisguised or sophisticated in the sense of reflecting psychodynamic theorizing or elaborate multivariate approaches to scale construction. Simple self-ratings were also obtained. Results showed that (a) short scales were as valid on the average as long scales in all three studies, even though some of the short scales were merely subsets of the long scales; (b) simple scales were as valid as sophisticated scales in all three studies; and (c) self-rating scales were as valid as questionnaire scales in two studies, but not in the third. The discussion focuses on certain unrealistic assumptions of the Spearman-Brown formula and on the notion of personality assessment as a noise-afflicted communication process.