Maternal employment and child cognitive outcomes: the importance of analytic approach

J. Brooks-Gunn, W. J. Han, and J. Waldfogel (2002) and the National Institute of Child Health and Human Development Early Child Care Research Network (ECCRN; 2000b) came to different conclusions about the effects of maternal employment--although they were addressing similar questions using the same data set. Brooks-Gunn et al. concluded that maternal employment in infancy has a negative effect on children's cognitive abilities at age 3, whereas the ECCRN found that early nonmaternal care is not related to children's cognitive abilities in their first 3 years. The authors account for this difference by comparing 2 approaches to data analysis: a top-down testing of continuous variables (the approach used by the ECCRN, 2000b) and an a priori comparison approach that involves pairwise testing of specific dichotomous contrasts (the approach used by Brooks-Gunn et al., 2002). This comparison illustrates the critical importance of analytic approach. It also suggests that Brooks-Gunn et al.'s conclusion from this data set is overstated and should not be used on its own as the basis for practical or policy decisions.