Table 4.
Estimated Item Parameters and their Standard Errors From Graded Response Model with Differential Item Functioning tests (chi-squared estimate and p-value)
| Item | Language | Parameters and Std Error | DIF tests: Chi-square and p-values | |||||
|---|---|---|---|---|---|---|---|---|
| a (se) | b1 (se) | b2 (se) | Omnibus DIF: χ2(3) | a DIF: χ2(1) | b DIF: χ2(2) | |||
| Anchor | 1 | Both | 1.35 (0.15) | −1.34 (0.17) | −0.21 (0.11) | |||
| 4 | 2.59 (0.16) | −1.36 (0.08) | −0.46 (0.05) | |||||
| 7 | 2.23 (0.16) | −1.82 (0.12) | −0.9 (0.06) | |||||
| 8 | 2.57 (0.16) | −1.49 (0.09) | −0.44 (0.05) | |||||
| DIF Free | 3 | Both | 3.22 (0.22) | −1.48 (0.08) | −0.48 (0.04) | 11.2 (0.011) | 3.4 (0.065) | 7.8 (0.020) |
| 9 | 0.68 (0.13) | −4.56 (0.86) | −2.3 (0.45) | 1.0 (0.801) | ||||
| Showed DIF | 2 | English | 0.64 (0.04) | 0.31 (0.18) | 2.11 (0.21) | 98.2 (0.000) | 4.9 (0.027) | 93.2 (0.000) |
| Spanish | −0.8 (0.18) | 2.29 (0.23) | ||||||
| 5 | English | 3.31 (0.20) | −1.38 (0.09) | −0.45 (0.06) | 26.5 (0.000) | 0.1 (0.752) | 26.3 (0.000) | |
| Spanish | −1.56 (0.09) | −0.56 (0.05) | ||||||
| 6 | English | 2.42 (0.13) | −1.17 (0.09) | −0.17 (0.07) | 63.7 (0.000) | 0.1 (0.752) | 63.5 (0.000) | |
| Spanish | −1.33 (0.08) | 0.18 (0.06) | ||||||
Note: In columns 4–6 standard errors are in parenthesis and in columns 7–9 p-values are in parenthesis. In the IRT graded response model used, a is the discrimination parameter and b1 and b2 are the item difficulty or location parameters