| MEASUREMENT PROPERTIES | |
| Limitations | <5 European languages (English) |
| Observations |
The information was obtained from the seminal publication of the validation of Qualipsosex. A cross sectional observational study with a longitudinal component for responsiveness and test–retest reliability was performed in 12 centers in France including 7 dermatologists and 5 rheumatologists. Psychometric properties were examined according to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) check-list |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Internal consistency was excellent with a Cronbach’s a of 0.87 (CI 95% 0.83–0.90). |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
The reliability was assessed by the ICC in 35 patients who all considered that there had been “no change” in the overall assessment of change in their disease between baseline and day seven. The ICC was 0.93 (95% CI: 0.88–0.98). In these 35 patients the mean QSQ value was 16.1±9.2 at baseline vs 15.4± 10.6 at day 7. |
| C. Reliability interobserver or Measurement error | Not Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
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| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
The face and the content validity of the QSQ were established by the development of the questionnaire through the literature review, patient and physician interviews and the qualitative steps of the questionnaire development. |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Not Tested |
| Cross-cultural validity | Not Tested |
| Brief Description |
The construct validity of the QSQ was assessed in 114 patients who filled in the baseline QSQ using an exploratory factorial analysis. Kaiser’s “Measure of Sampling Adequacy” (MSA) showed a good adequacy to the factorial analysis model with an MSA=0.84. |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
The criterion validity was estimated using the Pearson correlation coefficient between the QSQ score and question 9 of the adapted DLQI in the 112 patients who completed the baseline QSQ. The correlation between the two scales was moderate with a Pearson correlation coefficient of 0.48 (95% CI: 0.32–0.61). |