Chronic Pain Patients: (Kerns et al, 1985)
- Excellent correlation between the affective stress dimension of the WHYMPI and the State-Trait Anxiety Inventory-State form (STAI-S): r = 0.86
- Excellent correlation between the affective stress dimension of the WHYMPI and the Beck Depression Inventory (BDI): r = 0.76
- Excellent correlation between affective stress dimension of the WHYMPI and the Depression Adjective Check List (DACL): r = 0.68
- Excellent correlation between measured support from others by the WHYMPI and the Marital Adjustment Scale (MAS): r = 0.71
- Adequate correlation between measured support from others of the WHYMPI and the Multidimensional Health Locus of Control (MHLC)-Powerful Others Scale: r = 0.35
- Adequate correlation between the activity level dimension of the WHYMPI and the McGill Pain Questionnaire (MPQ)- Total Pain Rating Index and Present Pain Intensity: r = 0.47 and 0.44, respectively
Chronic Pain: (Riley et al., 1999; n = 472 mean age = 44.1 (13.6)) Construct validity of each section of the WHYMPI was assessed with principal axis factor analysis procedure.
Section one yielded four factors with an eigenvalue greater than 1, which accounted for 69.6% of total variance:
- interference scale
- support scale
- self-control and negative mood scale (lack of psychological adjustment)
- pain severity scale
Problematic cross loading across factors were observed for 3 items: item 12 (amount of suffering experienced because of pain), item 13 (pain affects marital and family relationships), and item 19 (pain affects friendships with other than family members).
Section two yielded three factors with an eigenvalue greater than one, which accounted for 62.7% of variance:
- solicitous response scale
- punishing response scale
- distracting response scale
Cross loadings were observed for item 3 (reads to me) and item 6 (talks to me to take my mind off the pain), providing evidence for lack of divergence between distracting and solicitous scale items.
Section 3 yielded three factors with an eigenvalue greater than 1, which accounted for 54% of total variance:
- household chores scale
- outdoor work scale
- activities away from home scale
- social activities scale
No cross loadings observed for this section.
Chronic Pain in Elderly Adults (76-99 years old): (Jakobsson et al., 2006; n= 175 mean age = 84.9 (5.4); Swedish sample- translated version)
- The full length instrument showed acceptable validity and reliability for some parts of the instrument but showed no satisfactory factor structure was found for section 1 or section 2 of the instrument. Overall, It had acceptable convergent and discriminant validity, but the factor analysis did not show a good model fit. The brief screening version, however, showed higher reliability and validity.
Low Back Pain: (Bernstein et al., 1995; n = 194, mean age = NR; SD = NR)
Construct validity of the WHYMPI was assessed with factor analysis with commonly utilized measures found relevant to pain including:
- Pain duration in days
- Self-efficacy: worry
- Self-efficacy: confidence
- Pain disability
- The somatization scale of the Symptom Checklist 90 revised (SCL-90-R)
- The GSI index of the SCL-90-R
Results found that the MPI possesses convergent validity because it significantly correlates with other measures of psychosocial adjustment in pain patients.