The Center for Epidemiologic Studies Depression Scale (CES-D) is one of the most widely used measures of depressive symptoms in research today. The original psychometric work in support of the CES-D (Radloff, 1977) described a 4-factor model underlying the 20 items on the scale. Despite a long history of evidence supporting this structure, researchers routinely report single-number summaries from the CES-D. The research described in this article examines the plausibility of 1-factor model using an initial sample of 595 subjects and a cross-validation sample of 661. After comparing a series of models found in the literature or suggested by analyses, we determined that the good fit of the 4-factor model is mostly due to its ability to model excess covariance associated with the 4 reverse-scored items. A 2-factor model that included a general depression factor and a positive wording method factor loading only on those 4 items had fit that was nearly as good as the original 4-factor model. We conclude that although a 1-factor model may not be the best model for the full 20-item CES-D, it is at least plausible. If a unidimensional set of items is required (e.g., for a unidimensional item response theory analysis), by dropping 5 items, we were able to find a 1-factor model that had very similar fit to the 4-factor model with the original 20 items.
- Factor analysis