“…As we were interested in interpersonal traits that may be related to hostile and responsive parenting, self‐ and informant‐reported subscales assessing the following traits were included in this study: Aggression (two items; α self = .31; α informant = .45; AIC self = .18; AIC informant = .29; SB self = .31; SB informant = .45; e.g., easy to lose temper and hold on to anger vs. does not lose temper easily and quick to forgive and forget), negative temperament (NT; three items; α self = .77; α informant = .79; AIC self = .53; AIC informant = .56; e.g., moody and emotionally labile vs. even‐tempered) and mistrust (two items; α self = .61; α informant = .69; AIC self = .44; AIC informant = .53; SB self = .62; SB informant = .69; e.g., seldom trust others and expect to be let down by others vs. trust easily). Our reliability coefficients are generally similar to those reported by Harlan and Clark (1999) and others (Kotelnikova, Clark, Vernon, & Hayden, 2015; Ready & Clark, 2002; Ready, Watson, & Clark, 2002; Schalet, Durbin, & Revelle, 2011), except for self‐reported aggression, which was relatively low (although all internal consistency values are within the expected range for scales with only two or three items). We provide average interitem correlations (AIC) as indices of the scales' internal consistency independent of scale length (Clark & Watson, 2019), as well as the Spearman‐Brown (SB) statistic for the aggression and mistrust scales, another reliability index recommended for two‐item scales (Eisinga, Te Grotenhuis, & Pelzer, 2013).…”