VALIDATION DATA

MEASUREMENT PROPERTIES
Limitations <5 European languages (English)
Observations
1. RELIABILITY
A. Internal Consistency Not Tested
Cronbach's (Describe)
B. Reliability intraobserver or test-retest Tested
Continuous scores: intraclass
correlation coefficient (ICC)
Dichotomus: Cohen kappa (Describe)

ICC=  0.89 (95% CI 0.83, 0.93)

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 instrument was piloted by means of a self‐administered questionnaire with 13 persons with OA, followed by a brief interview that was designed to assess their understanding of the questionnaire. Content validity was deemed satisfactory after patient research partners and expert panel groups judged the OA-QI items to be relevant.

B. Construct Validity:
Structural validity
Tested
Hypotheses-testing Tested
Cross-cultural validity Tested
Brief Description

Construct validity was acceptable with all six predefined hypotheses confirmed.

C. Criterion validity Not Tested
Comparison with a 'gold standard' Continuous scores:
correlations, ROC curves Dichotomus:
Sensitivity & Specificity (Describe)