Ross and Hill (2000) developed the Family Unpredictability Scale to measure and understand inconsistency in family behaviors and regulatory systems. Parents who reported having a child with an emotional, behavioral, or attention problem, compared to parents not reporting such problems, also reported higher family unpredictability. In addition, family unpredictability was associated with more self-reported depression and anxiety among parents.

Other research has asked children to describe parental inconsistency. Retrospective accounts of inconsistent parental affection have been correlated with young women's depression and bulimic eating behavior (Scalf-McIver & Thompson, 1989) and self-criticism (McCranie & Bass, 1984). Perceptions of parental discipline inconsistency (e.g., "my mother promises me a reward and then later forgets about it") have been associated with negative outcomes such as aggression (Hall, Herzberger, & Skowronski, 1998) and anxiety (Kohlmann, Schumacher, & Streit, 1988). In an unusual longitudinal study, Hightower (1990) found that teenagers who perceived that their parents were reasonable and consistent in their attitudes and rules had better psychological health at age 50, whereas other parenting domains, including nurturance, did not relate to subsequent mental health. Perhaps the consistency (as well as fairness) assessed during adolescence were markers of a predictability schema or belief system, described in detail below, and these ongoing perceptions helped explain subsequent mental health.

Another family-based source of unpredictability is living with an alcoholic parent. Researchers and clinicians describe families headed by an alcoholic parent as unpredictable and chaotic. For example, families with an alcoholic parent are more likely to involve inconsistent parental affection (Benson & Heller, 1987), abuse (Jones & Houts, 1992), and marital disruption (Black, Bucky, & Wilder-Padilla, 1986). Familial unpredictability may be more severe or detrimental when the alcoholic parent relapses (Moos & Billings, 1982), is an episodic or binge drinker (Jacob, Krahn, & Leonard, 1991) or is an "antisocial" or "Type II" alcoholic, due to greater impulsivity (Ichiyama, Zucker, & Fitzgerald, 1994) and instability (Babor et al., 1992). Ross and Hill (2001) found that retrospective perceptions of parental unpredictability (perceiving parents as unpredictable, inconsistent regarding rules/discipline, delaying punishment, and not acting on threats) mediated the relationship between having an alcoholic parent and young adults' alcohol consumption. Thus, problematic drinking was not associated with parental alcoholism per se, but rather with parental unpredictability, which was more common among alcoholic parents.

Lenore Terr (1991) is a psychiatrist who works with children who have experienced a variety of "externally generated horrors" (p. 11) that include both onetime unanticipated events (e.g., witnessing a murder or suffering a near-death experience) and variable or multiple traumas (e.g., ongoing sexual or physical abuse). Terr writes, "the sense of a severely limited future, along with changed attitudes about people and life, appears to be important in the trauma and extreme stress disorders originating in childhood." (p.13). She adds that this is particularly striking because nontraumatized children's ideas about the future are almost limitless.