Table 2.
Predefined expected correlations between Medical Outcomes Study Short Form 36 (SF‐36) and Skindex‐29 change scores and global rating of change (GRC) scales
| GRC scale measuring similar construct (expected high correlation) | GRC scale measuring related, but dissimilar construct #1 (expected moderate correlation) | GRC scale measuring related, but dissimilar construct #2 (expected moderate correlation) | GRC scale measuring unrelated construct (expected low correlation) | |
|---|---|---|---|---|
| SF‐36 GH | Overall health | Physical condition | Emotional wellbeing | Appearance |
| SF‐36 BP | Pain | Overall health | Symptom severity | Appearance |
| SF‐36 PF | Physical condition | Overall health | Pain | Appearance |
| SF‐36 SF | Social relationships and social activities | Overall health | Ability to perform work, study or school‐related activities | Mobility of affected body part |
| SF‐36 MH | Emotional wellbeing | Overall health | Social relationships and social activities | Mobility of affected body part |
| SF‐36 RP | Ability to perform work, study or school‐related activities | Overall health | Physical condition | Appearance |
| SF‐36 RE | Ability to perform work, study or school‐related activities | Overall health | Emotional wellbeing | Mobility of affected body part |
| SF‐36 PCS | Physical condition | Overall health | Pain | Appearance |
| SF‐36 MCS | Emotional wellbeing | Overall health | Social relationships and social activities | Mobility of affected body part |
| SF‐36 sum | Overall health | Physical condition | Symptom severity | Appearance |
| Skindex S | Symptom severity | Overall health | Pain | Appearance |
| Skindex F | Social relationships and social activities | Overall health | Ability to perform work, study or school‐related activities | Appearance |
| Skindex E | Emotional wellbeing | Overall health | Social relationships and social activities | Mobility of affected body part |
| Skindex sum | Overall health | Emotional wellbeing | Symptom severity | Appearance |
Per SF‐36 and Skindex‐29 subscale, a GRC scale measuring change in a similar construct was determined, with which a high correlation was expected. Moderate correlation was expected with GRC scales measuring change in a related, but dissimilar construct (two defined per subscale). Low correlation was expected with a GRC scale measuring change in an unrelated construct. Correlation was interpreted as high (> 0·5), moderate (0·3–0·5) or low (< 0·3). GH, general health; BP, bodily pain; PF, physical function; SF, social function; MH, mental health; RP, role physical; RE, role emotional; PCS, physical health component score; MCS, mental health component score; S, symptoms; F, functioning; E, emotions.