Table 3.
Results of piecewise growth model fitted to IRT scores calculated under the assumption of no DIF and to IRT scores accounting for DIF.
| Assuming no DIF | Accounting for DIF | |||||
|---|---|---|---|---|---|---|
| Parameter | Estimate | SE | p | Estimate | SE | p |
| Latent intercept factor | ||||||
| Intercept | .335 | .053 | < .0001 | .337 | .052 | < .0001 |
| Study effect | -.457 | .058 | < .0001 | -.445 | .057 | < .0001 |
| Gender effect | -.089 | .049 | .0679 | -.086 | .047 | .0709 |
| Parent alcoholism effect | .167 | .054 | .0021 | .165 | .053 | .0020 |
| Residual variance | .402 | .025 | < .0001 | .386 | .024 | < .0001 |
| First latent slope factor (age 2-7) | ||||||
| Intercept | .101 | .036 | .0048 | .107 | .035 | .0025 |
| Gender effect | .043 | .031 | .1745 | .039 | .031 | .2128 |
| Parent alcoholism effect | -.010 | .028 | .7151 | -.011 | .027 | .6862 |
| Residual variance | .000* | .000* | ||||
| Second latent slope factor (age 7-17) | ||||||
| Intercept | -.041 | .016 | .0131 | -.038 | .016 | .0178 |
| Study effect | .025 | .017 | .1357 | .031 | .017 | .0601 |
| Gender effect | -.041 | .012 | .0010 | -.042 | .012 | .0007 |
| Parent alcoholism effect | .022 | .013 | .0889 | .023 | .013 | .0774 |
| Residual variance | .002 | .001 | .0320 | .002 | .001 | .0286 |
Note. N = 1026.
*
This parameter estimate was constrained to zero to arrive at proper solution.