| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations |
74 language versions, 12 fully validated The disease-specific ASQOL questionnaire can multidimensionally assess the QoL in patients, including physical functioning, role physical, bodily pain, general health, vitality, social function, role emotion, and mental health.
|
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
α = 0.89-0.92 The pooled Cronbach’s α coefficients scored as high and moderate quality of evidence of the ASQOL was 0.89 (95% CI 0.86 to 0.92) |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
ICC = 0.91 (UK) ICC = 0.92 (The Netherlands) In a systematic review, adequate to very good test–retest reliability of high quality of evidence was found for the ASQOL questionnaire (ICC values of 0.44 to 0.933). |
| C. Reliability interobserver or Measurement error | Not Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
|
| 2. VALIDITY | |
| A. Content validity: face validity | Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
The ASQoL was developed in partnership between a group in the United Kingdom and the Netherlands following a series of patient interviews. An item bank was generated and distilled following a Rasch analysis and the removal of problematic items. An interview study among five patients found that most of the concepts were captured. |
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description |
Scaling properties were tested using Rasch analyses. Conceptually, the ASQOL is based on a needs-based model of health. |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
ASQoL scores differed significantly by whether the respondent was having a good or a bad day (disease activity), self perceived general health status, and self perceived AS severity. The convergent validity of the ASQOL questionnaire is weak to good. |