The measurement of psychological states by use of factors derived from a combination of items from mood and symptom checklists

The similatities in structure and usage of two widely used adjective checklists, the Profile of Mood States (POMS) and Symptom Checklist (SCL), suggested the feasibility of pooling the items from the two scales into a single factor analysis. This procedure was clinically appealing, statistically sound, and provided an efficient method to reduce and refine assessments of psychopathology. Data from 413 Miami Symptomatic Volunteers were used in this factor analysis. Nine factor dimensions were found to meet the dual criteria of statistical salience and clinical meaningfulness. The results demonstrated the factorial stability of the SCL and the POMS and identified the dimensions of psychopathology in which items from the two scales tended to complement each other in factor structure. Some factors were found to be unique to each scale. In addition, it was found that pooling the items from both scales yielded two new factor dimensions that were not previously available from either of the individual scales.