This chapter covers the methods and measures used in the ERA study, with a special focus on age 15 outcomes. First, we outline the sample participation rate for the 15-year follow-up-the percentages in all cases referring to the numbers at the time of initial sample contact. We then describe the measures used in this monograph, starting with those obtained at first contact with respect to functioning at the time of leaving institutional care. Because the group definitions relevant to the follow-up at age 15 are based on assessments at 6 and 11 years of age, we deal with the measures in those assessments first. At 11 years of age, we used a range of specific cognitive tests that might be of predictive value and those are detailed next. Then we discuss measures employed at the 15-year follow-up and those relevant to possible autism as used by Rutter in the separate assessment at 18-20 years. The monograph is structured around the possibility of deprivation-specific psychological patterns (DSPs), and hence on the strategies needed to test for them (see Rutter et al. in chapter I). Accordingly, the next section of this chapter deals with that strategy and details the measures taken to test the assumption's underlying the strategy. In our published papers concerning the 11-year follow-up, we tested whether outcomes were affected by the fact that some parents adopted mainly for altruistic reasons and others because of infertility-affected outcomes. Here we repeat this analysis in relation to DSPs. Similarly, we report findings on gender differences. The longitudinal study involved obtaining DNA for genotyping to examine the possibility that genetic features moderated the young people's response to institutional deprivation. Accordingly, in the next section of the chapter, we outline our genotyping approach. The final section of this chapter describes the statistical techniques we employed in our analyses.