Table 1 Predetermined hypotheses for testing the validity of the Dutch version of WOSI: expected and observed correlations

1. WOSI and OSIS

≥ 0.7

0.82

2. WOSI and SST

≥ -0.6

- 0.66

3. WOSI and OSS

≥ 0.6

0.79

4. WOSI and DASH

≥ 0.6

0.81

5. Correlation between WOSI and OSIS, both measuring a disease-specific construct should be at least 0.1 higher compared with all other correlations.

6. Correlation between similar WOSI and SF-36 domains should be higher compared with dissimilar domains.

7. Correlation between similar WOSI and SF-36 domains should be ≥ 0.4.