Child Abuse Potential (CAP) Inventory

Psychologists are often asked to evaluate and to provide testimony about parental capacity. The Child Abuse Potential (CAP) Inventory, a measure originally designed to screen parents for child physical abuse risk, is frequently used as a measure of general parental capacity. The CAP Inventory is a 160-item, forced-choice (agree/disagree) self-report questionnaire. It contains a 77-item physical abuse scale, six descriptive factor scales (distress, rigidity, unhappiness, problems with child and self, problems with family, and problems from others), and three validity scales (lie, random response, and inconsistency). The three validity scales are used in different combinations to form three response distortion indexes (faking good, faking bad, and random response). The CAP Inventory also contains two special scales: the ego-strength and loneliness scales. The Inventory has been translated into more than 25 languages, including multiple Spanish translations. Although the available data on the translated versions of the CAP Inventory are generally positive, the amount of published data on the reliability and validity of the CAP Inventory translations is highly variable.

Child Abuse Potential Inventory Background

An original pool of CAP Inventory items was developed following an exhaustive review of the theoretical and empirical literature that described parental psychological and interpersonal risk factors thought to be associated with child physical abuse. In constructing the CAP Inventory, an effort was made to avoid using items that represented static risk factors. Items were included in the current 77-item abuse scale based on their ability to distinguish between known child physical abusers and matched comparison parents in validation studies. Furthermore, in selecting the final list of abuse scale items, an effort was made to exclude items that were correlated with demographics characteristics.

Child Abuse Potential Inventory Reliability

Internal consistency estimates for the CAP Inventory physical abuse scale range from .92 to .96 for general population parents and from .95 to .98 for child physical abusers. Internal consistency estimates are similar across gender, ethnic, and educational groups. Temporal stability (test-retest reliability) estimates for the CAP physical abuse scale are .91, .90, .83, and .75 for 1-day, 1-week, 1-month, and 3-month intervals, respectively.

Child Abuse Potential Inventory Validity

Extensive construct validity data indicating the expected relationships between CAP Inventory abuse scores and risk factors have been reported. For example, the expected relationships have been found between a respondent’s CAP abuse scores and his or her childhood history of observation and receipt of abuse, and the respondent’s childhood history of observing marital violence. CAP abuse scores also are associated (in the expected manner) with psychophysiological reactivity, neuropsychological problems, social isolation/lack of social support, negative family interactions, adult attachment problems, low self-esteem/ego-strength, stress/distress, inadequate knowledge of child development, belief in corporal punishment, negative perceptions of child behaviors, negative evaluations of child behaviors, low expectations of children, negative attributions (e.g., hostile intent), authoritarianism, depression, anxiety, anger/hostility, aggression, mental health problems/psychopathology, alcohol/drug use, problems in coping, lack of empathy, problems in parent-child interactions, use of harsh discipline strategies, and lack of positive parenting behaviors.

Concurrent validity studies report abuse scale correct classification rates in the 80% to low 90% range. Predictive validity data indicate that elevated abuse scores in high-risk parents (where participants were tested before interventions) are significantly related to later cases of child physical abuse. In addition, numerous studies have reported that elevated parental CAP abuse scores are predictive of child problems. For example, in a prospective study, before and after controlling for obstetric risk factors, scores on an abbreviated version of the CAP abuse scale were predictive of neonatal morbidity. In another prospective study, before and after controlling for problematic parenting orientations, CAP abuse scores were predictive of children’s later intelligence and adaptive behaviors.

In summary, although elevated CAP Inventory abuse scores have been shown to be predictive of later confirmed cases of child physical abuse, the large body of available construct validity data supports the view that the CAP abuse scale may have even more utility in detecting parents who are at high risk for a broad array of parenting problems (as outlined above) and is useful in detecting parents who are likely to have children who have problems in their physical and psychosocial development. Independent evaluations of the CAP Inventory psychometric data have produced similar conclusions. For example, with respect to testimonial admissibility, the CAP Inventory has been judged to meet the Daubert standard as a measure of parental capacity.


  1. Milner, J. S. (1986). The Child Abuse Potential Inventory: Manual (2nd ed.). DeKalb, IL: Psytec.
  2. Milner, J. S. (2006). An interpretive manual for the Child Abuse Potential Inventory (2nd ed.). DeKalb, IL: Psytec.
  3. Yanez, Y., & Fremouw, W. (2003). The application of the Daubert standard to parental capacity measures. American Journal of Forensic Psychology, 22(3), 5-28.

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