| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations |
Psychometric properties of the ShortMAC are often reported separatedly in the scales that compose it: WOMAC-F and WOMAC-P |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
WOMAC- F: internal consistency was good, with Cronbach alpha: 0.88 to 0.95. |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
WOMAC- F: excellent test-retest reliability, with Lin's concordance correlation coefficient (rho(c)): 0.85 to 0.94. |
| 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) |
Development of the WOMAC involved expert opinion (including rheumatologists and epidemiologists), reviews of existing instruments, and surveys of patients with hip and / or knee OA. For developing the ShortMAC, expert opinion was also included. |
| B. Construct Validity: Structural validity |
Not Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Not Tested |
| Brief Description | |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
Spearman’s correlation coefficient between the two scales (ShortMAC and WOMAC) was 0.96. |