Abstract
Rasch analysis was used to illustrate the usefulness of item-level analyses for evaluating a common therapy outcome measure of general clinical distress, the Symptom Checklist-90-Revised (SCL-90-R; Derogatis, 1994). Using complementary therapy research samples, the instrument's 5-point rating scale was found to exceed clients' ability to make reliable discriminations and could be improved by collapsing it into a 3-point version (combining scale points 1 with 2 and 3 with 4). This revision, in addition to removing 3 misfitting items, increased person separation from 4.90 to 5.07 and item separation from 7.76 to 8.52 (resulting in alphas of .96 and .99, respectively). Some SCL-90-R subscales had low internal consistency reliabilities; SCL-90-R items can be used to define one factor of general clinical distress that is generally stable across both samples, with two small residual factors.
| Original language | English |
|---|---|
| Pages (from-to) | 359-372 |
| Number of pages | 13 |
| Journal | Psychological Assessment |
| Volume | 18 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Dec 2006 |
Keywords
- Rasch analysis
- therapy
- clinical distress
- psychotherapy
- social psychology
Access to Document
- Elliott et al., 2006: Deconstructing Therapy Outcome Measurement With Rasch Analysis of a Measure of General Clinical Distress: The Symptom Checklist–90–Revised
Copyright 2006 by the American Psychological Association. DOI: 10.1037/1040-3590.18.4.359. This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.