Table 5.
Analyses of the WPI, SS scale, and total scores by clinical population to assess criterion validity.
| Bonferroni post hoc analyses |
||||||
|---|---|---|---|---|---|---|
| Surgery (1) | Headache (2) | Chronic pain (3) | Group differencesa | Mean difference (SE)b | 95% CI | |
| WPI, M (SD) | 2.4 (2.0) | 4.6 (3.8) | 6.0 (5.4) | F2,237 = 17.55, P < 0.001, η2 = 0.13 | 1:2 = −2.20 (0.70) 1:3 = −3.56 (0.60) |
−3.89, −0.51* −5.02, −2.11* |
| SS scale, M (SD) | 3.6 (2.5) | 6.6 (2.1) | 6.3 (2.6) | F2,222 = 33.09, P < 0.001, η2 = 0.23 | 1:2 = −3.04 (0.44) 1:3 = −2.72 (0.38) |
−4.09, −1.98* −3.63, −1.80* |
| Total score, M (SD) | 6.5 (3.5) | 11.2 (4.9) | 12.3 (7.0) | F2,222 = 23.74, P < 0.001, η2 = 0.18 | 1:2 = −4.73 (0.99) 1:3 = −5.78 (0.86) |
−7.11, −2.35* −7.86, −3.69* |
aANOVA (Mean score × Group).
bMean difference was calculated as the first variable minus the second; thus, negative values indicate greater scores in headache and chronic pain samples.
*P < 0.001.
WPI = Widespread Pain Index; SS = Symptom Severity; CI = confidence interval; ANOVA = analysis of variance.