Methodological Considerations in Scale Refinement with Diverse Populations: A Case Example Using the CES-D with a Community Sample of American Indian Women.

Although many psychometric assessments are used extensively in population-based research to determine psychopathology, these tools have not been thoroughly validated or appropriately adapted for use in diverse populations. Indeed, depression measurement studies among American Indian and female populations are scarce, omitting key opportunities to tailor psychological measurement for this population. To build psychometric evidence of measures in this population, we used a procedural method to examine a standard psychological instrument-the Center for Epidemiological Studies Depression Scale (CES-D)-with a community sample of southeast American Indian women. Our results showed strong psychometric reliability of the 20-item CES-D. The "effort" item presented diminished validity, as demonstrated by a negative counter-intuitive item-to-total correlation (ITC) value. Dropping the "effort" item resulted in a 19-item scale with a better fit in the within-group examination of community-based American Indian women. Compared to the 20-item CES-D scale, the revised 19-item measure ("effort" item removed) resulted in minimal changes to women's depression categories. However, we did detect patterns in shifts such that the 19-item scale generally underestimated (i.e., placed women in a lower category) depressive symptoms compared to the 20-item scale. Depending on their study goals, researchers engaging in population-based research should carefully weigh the use of original scales that allow for consistency in reporting with refined scales that fit psychometrically. We present the outlined method as a tool that expands on current approaches in scale refinement, and aids researchers in making more informed decisions regarding refined scales with diverse populations.