three to five times, (5) six to ten times, (6) more than 10 times. While there was a long interval between the age at which maltreatment was assessed and the time period about which it was assessed, retrospective endorsements of child sexual maltreatment (Williams 1992), physical maltreatment (Berger et al. 1988), and other adverse childhood events (Brewin et al. 1993) are typically valid. Also, a review of the heritability of parenting and other ‘environmental’ variables (Kendler and Baker 2007) suggested that self-report and informant-report yielded similar heritability estimates, and the authors concluded that twin studies of environmental variables largely reflect ‘actual behavior’ rather than ‘only perceptions’.
