the families of target youth who did (n = 461) and did not (n = 78) agree to provide DNA (to conserve space, the means and standard deviations for these tests are not presented). For these analyses, t tests were used to compare all of the demographic and study measures except gender and maternal marital status, for which chi-square tests were used. No differences emerged on demographic or study variables between the families with pretest data and those with long-term follow-up data. Neither did any differences emerge between families or youth who did or did not agree to provide DNA.
