To examine the potential effect of selective placement in the EGDS, we correlated birth parent characteristics with adoptive family characteristics that were unlikely to be influenced by evocative effects (e.g., demographic characteristics). Not one of these relationships was statistically significant. To examine the potential effect of openness, we created an openness composite comprised of birth mother, adoptive mother, and adoptive father reports of openness, the level of contact between the birth and adoptive parents (five scales ranging from 1 [never] to 5 [daily]), and the extent of knowledge about each other (six scales ranging from 1 [a lot] to 4 [nothing]). The results of these analyses suggested that the number of significant correlations between the openness composite and our birth parent and adoptive family measures approximated levels expected by chance, suggesting negligible impact of openness on model estimates. Together with the selective placement results, these analyses support the adoption design assumptions of minimal selective placement and minimal bias due to the level of openness in the EGDS sample, although we will continue to examine these processes as the sample matures.
