A shortened version of the Parental Bonding Instrument (PBI; Parker et al. 1979; Parker, 1990), a widely used parenting scale, was administered in wave 1. Participants reported on the parenting they received during childhood using four response options ranging from 1 to 4 (`not at all' to `a lot'). Previous factor analyses of these PBI items support three scales reflecting parental protectiveness, authoritarianism, and warmth (Kendler, 1996). Participants missing one or more items on a single PBI scale were coded as missing on that scale. The distributions of parental warmth scores were positively skewed and scores were log-transformed prior to analysis.
