Table 7. Differential item functioning analyses of the Well-being Numerical Rating Scales (WB-NRSs) across Italian and Canadian samples.
| Total | a | b | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Item | X2 | df | p | X2a | df | p | X2 | df | p |
| WB-NRS 1 | 13.7 | 9 | 0.131 | 1.3 | 1 | 0.260 | 12.5 | 8 | 0.131 |
| WB-NRS 2 | 12.5 | 10 | 0.252 | 0.0 | 1 | 0.861 | 12.5 | 9 | 0.187 |
| WB-NRS 3 | 10.6 | 10 | 0.392 | 2.8 | 1 | 0.094 | 7.8 | 9 | 0.558 |
| WB-NRS 4 | 8.6 | 10 | 0.567 | 0.6 | 1 | 0.438 | 8.0 | 9 | 0.531 |
| WB-NRS 5 | 19.4 | 10 | 0.033 | 10.5 | 1 | 0.001 | 9.0 | 9 | 0.440 |
Note. DIF was calculate under Samejima’s Graded Response Model. α was considered significant at .01 (0.05/5) in order to adjust for multiple comparisons (Bonferroni correction). a = discrimination, b = category threshold.