One might similarly question the reliability of our measure of lifetime maximum consumption. Self-reports of drinking behavior generally agree with reports of other informants (Guze, Tuason, Stewart, & Picken, 1963; Maisto, Sobell, & Sobell, 1979). If anything, alcoholics are more likely to report significant problems than others (Guze et al., 1963), suggesting greater knowledge of their own problematic drinking (Maisto et al., 1979). An assessment of the lifetime maximum consumption measure used here found good test-retest reliability over a 10-week period (r = .70) (Grant et al., 2003). However, to our minds the best evidence for the validity of this measure, even if estimates may not be perfectly accurate, comes from the fact that its associations replicated so faithfully across our two cohorts and that parallel effects were found for both parents.
