Although there was a lower response among families of minority groups (70 %) than among white families (84 %), (p <.01), t - tests and chi - square analyses indicated that minority - group respondents did not differ from minority - group
nonrespondents on any birth status or sociodemographic variable (p >.05).
Finally, to account for the minor differences between respondents and
nonrespondents that we did observe, the test scores of children who, based
on their demographic characteristics, were more likely to attend follow - up sessions were weighted less heavily, while the test scores of children who were less likely to attend follow - up sessions, but nevertheless did, were weighted more heavily.