Table 1.

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

	Expected correlations	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.

Correlations were calculated using the total WOSI score.