(see Figure 1). Twins in the final sample are identified by the target age for their intended assessment: 11-year-olds (M=11.70, SD=0.43) at intake, 14-year-olds (M=14.77, SD=0.51) at the first follow-up, and 17-year-olds (M=17.99, SD=0.60) at the second follow-up. Because some individuals participated after their targeted assessment year, and this became more likely with each follow-up, actual ages at participation were somewhat higher than the target age. For convenience and to maintain consistency with previous reports, we refer to each assessment by the targeted age.
