In this chapter, we turn to the question of whether there is evidence of an association between children's development and the quantity or dosage of ECE across several large studies. As follow-up to the results summarized in the literature review, it is important to control adequately for selection effects in studying effects of dosage. There is also a need to examine different measures of dosage to see if consistent patterns of findings emerge across different measurement approaches. Accordingly, in this chapter, we will summarize analyses by using more rigorous approaches to controlling for selection than those used in previous research and will adopt several approaches to operationalizing dosage. Again, we are seeking replicated findings, as indicated in this section by similar significant findings across projects in analyses of dosage.