Table 3.
DIF classification criteria | |||||||
---|---|---|---|---|---|---|---|
Component | H 0 Hypotheses | Wald chi-square | p-value | Δ Nagelkerke R 2 | Jodoin and Gierl (2001) | ETS | |
Recognition | |||||||
No non-uniform DIF | −0.434 | 0.619 | .431 | 0.004 | Negligible DIF | – | |
No uniform DIF | 0.283 | 0.250 | .617 | 0.002 | Negligible DIF | Negligible DIF | |
External cause | |||||||
No non-uniform DIF | −0.055 | 0.027 | .869 | 0.000 | Negligible DIF | – | |
No uniform DIF | −0.100 | 0.081 | .776 | 0.000 | Negligible DIF | Negligible DIF | |
Desire | |||||||
No non-uniform DIF | 0.340 | 2.556 | .110 | 0.007 | Negligible DIF | – | |
No uniform DIF | −0.382 | 1.796 | .180 | 0.005 | Negligible DIF | Negligible DIF | |
Belief | |||||||
No non-uniform DIF | 0.235 | 3.169 | .075 | 0.010 | Negligible DIF | – | |
No uniform DIF | 0.393 | 2.841 | .092 | 0.009 | Negligible DIF | Negligible DIF | |
Memory | |||||||
No non-uniform DIF | 0.248 | 1.909 | .167 | 0.006 | Negligible DIF | – | |
No uniform DIF | −0.216 | 0.660 | .416 | 0.002 | Negligible DIF | Negligible DIF | |
Regulation | |||||||
No non-uniform DIF | −0.274 | 1.905 | .168 | 0.005 | Negligible DIF - | ||
No uniform DIF | 0.393 | 2.063 | .151 | 0.005 | Negligible DIF | Negligible DIF | |
Hiding | |||||||
No non-uniform DIF | −0.366 | 3.314 | .069 | 0.008 | Negligible DIF | – | |
No uniform DIF | −0.053 | 0.037 | .848 | 0.000 | Negligible DIF | Negligible DIF | |
Mixed | |||||||
No non-uniform DIF | −0.243 | 1.085 | .298 | 0.003 | Negligible DIF | – | |
No uniform DIF | 0.094 | 0.103 | .748 | 0.000 | Negligible DIF | Negligible DIF | |
Morality | |||||||
No non-uniform DIF | −0.264 | 1.506 | .220 | 0.006 | Negligible DIF | – | |
No uniform DIF | 0.486 | 2.400 | .121 | 0.009 | Negligible DIF | Negligible DIF |
H 0 Hypotheses: No non-uniform DIF (H o: β 3 = 0 (Model 3)). No uniform DIF (H o: β 2 = 0 (Model 2))
coefficient calculated in the LR model 3 () and LR model 2 (). > 0 indicate DIF in favour of the reference group (girls), and < 0 indicate DIF in favour of the focal group (boys)
Wald chi-square: Wald statistic used to test the corresponding null hypotheses. That statistic follows a chi-squared distribution with one degree of freedom
Δ Nagelkerke R 2: Measure of the magnitude of DIF based on Nagelkerke’s R 2
DIF classification criteria: Classification of DIF based on the criteria proposed by Jodoin and Gierl (2001) and the Educational Testing Service (ETS): negligible DIF/ moderate DIF/ large DIF
This results have been obtained using the purified total test score (second stage). The total test score for each examinee was refined by removing the component belief that was found to show DIF in the first stage (−2 log likelihood [model 3-model 1] = 6.125171, df = 2, p = .047)