We sought to examine whether the EGDS sample was representative of the population from which it was drawn. Each participating adoption agency recorded the education, income, and age of all birth and adoptive parents who met the EGDS inclusion criteria during the study enrollment period. We compared the demographic information between triads who participated in the EGDS (N = 360 triads) with those of the eligible nonparticipants (N = 1169 triads available for analysis). As was reported elsewhere (Leve et al. 2007), only 2 of 11 comparisons reached statistical significance, and they proved trivial due to their small effect size. There were no significant demographic differences between birth mothers for whom birth fathers were recruited and birth mothers for whom birth fathers were not recruited.
