Intimate partner violence (IPV) encompasses physical violence, sexual violence, stalking, and psychological aggression by a current or former intimate partner [1]. In the United States of America (USA), according to National Intimate Partner and Sexual Violence Survey data from 2016 and 2017, almost 1 in 2 women and more than 2 in 5 men reported experiencing contact sexual violence, physical violence, or stalking by an intimate partner in their lifetime [2].

Numerous studies have assessed how commonly children live in homes where IPV occurs and estimate that just less than half to three-quarters of IPV incidents occur in homes with children [3–5]. In Fusco and Fantuzzo’s sample, 95% of children in homes with IPV experienced sensory exposure, such as hearing or seeing the violence. Nationally, 7% of children sampled for the 2011–2012 National Survey of Children’s Health had witnessed IPV, based on parent report [6]. In the 2011 National Survey of Children’s Exposure to Violence (NatSCEV), the oldest youth cohort of the study reported a 28.3% lifetime prevalence of witnessing interparental assault [7]. NatSCEV data also indicate that most (90%) saw the violence directly [8]. Hutchison and Hirschel analyzed interview data from over 400 women in abusive relationships and concluded that the presence of children in the home provided almost no influence on abuse deterrence, the nature or severity of the abuse or injury, nor the victim’s decisions regarding contacting police [9].

A meta-analysis of 118 studies identified a significant association between exposure to interparental violence and worse outcomes relative to non-witnesses or children from verbally aggressive homes, and that child witnesses’ outcomes were not significantly different from those of physically abused children [10]. The impacts on children associated with witnessing IPV are many, including behavioral issues, such as adjustment difficulties [11, 12], coping deficits [13], externalizing problems [14, 15], impulsivity [14], self-harm [16], substance misuse [17], precocious transitions [18]; mental health challenges like mood and anxiety disorders [16], and post-traumatic stress disorder [12, 19]; internalizing problems such as low self-esteem [10, 20], dysregulation [21], feelings of lacking safety or control [22]; insomnia [15], learning or academic difficulties [23], poor social relationships [15], problems with peers [12, 15]; exposure to other adverse childhood experiences [15, 17], risk-taking behaviors in adolescence and adulthood [24], future victimization from and/or perpetration of IPV in adulthood [4, 15, 25], and poorer health of future offspring [26].

Given these impacts, interventions to lower rates of childhood exposure to IPV have the potential to yield social and health benefits. One common intervention by states is the issuance of laws penalizing perpetration of IPV in the presence of children. We sought to inventory all relevant laws in the 50 states and the District of Columbia (D.C.) in the US and systematically evaluate their key attributes and heterogeneities so that later studies could evaluate their impacts.

Laws have far-reaching impacts, as they shape the society we live in and the lives of the citizenry. Understanding the effects of laws by measuring and evaluating them can help lawmakers craft legal approaches that best advance the intended objectives. There are many papers in the academic literature that assess policy interventions to address various aspects of IPV, but there is a shortfall of research into the effects of legal approaches to address child witnesses to IPV [27–30].

We began broad background research and, based on initial review of select relevant laws, drafted coding questions. We established a study protocol and updated it to document key decisions during the project. We searched WestLaw Edge, a web-based legal research service using a keyword and Boolean terms and connectors search string (see Supplementary Material: Appendix) in February 2022 for laws currently in effect and identified 1225 statutes and 561 regulations across 51 jurisdictions (50 states and D.C.) that we reviewed for relevance; 554 laws remained in our database[31]. We excluded documents that contained the word ‘hearsay’ from the search string to preclude results based on the search term ‘witness’ that pertain to the rules of evidence for courtroom witnesses, rather that child witnesses to IPV.

We cross-referenced the Child Welfare Information Gateway, a website supported by the Administration on Children and Families to provide information on child welfare law, and identified three additional relevant laws that were not captured in our search and added them [32]. In follow-up, we completed a supplemental WestLaw search using additional search terms based on the three laws identified by the Child Welfare Information Gateway and found no additional relevant laws. The search and coding methods used by the Child Welfare Information Gateway are not openly described; as such we anticipate this publication will provide a transparent and verifiable set that can be used for research.

Using a team that included some coders experienced in empirical legal research methods, some experienced in other qualitative research coding methods, and some novices, we piloted the coding instrument, having each team member individually code the same subset of laws then discussing and revising the instrument to address discrepancies. We coded the laws at 100% redundancy (2 coders per law) on a five-item instrument (see Supplementary Material: Appendix) using the Public Health Law Information Portal hosted by the Centers for Disease Control and Prevention. We coded for variation in the definition of ‘child’ and ‘witness,’ but did not analyze differences in definition of IPV for purposes of efficiency. We resolved all divergences through group discussion.

As of February 2022, 31 states had one or more laws related to children witnessing IPV (see Supplementary Material Table S1 for legal citations). Washington, D.C. did not have relevant laws. Table 1 presents descriptive statistics of the laws. Of the states with relevant laws, 28 (90%) specified what it meant for a child to ‘witness’ IPV, 22 (71%) specified the maximum age a child is considered a child witness, and 29 (94%) provided a specific penalty.

Example definitions for witnessing include “the child was in a position to see or hear the act” (Alabama), the act was committed “in the physical presence of a child or knowing that a child is present and may see or hear” (Idaho), and the act was committed “within thirty feet of or within the same residential unit as a child…regardless of whether the offender knows the age of the child or whether the offender knows the offense is being committed within thirty feet of or within the same residential unit as the child and regardless of whether the child actually views the commission of the offense” (Ohio).

The prescribed penalties and the maximum age of a child witness are described in Table 2. Where expressly defined within the relevant laws, the maximum age ranged from 13 to 17 years; most laws that included a specific definition selected 17 years as the maximum. Penalties prescribed vary. Most common was stricter sentencing (n = 21 states), which ranged from specific term requirements (such as, “the minimum term of imprisonment…. shall be double” [Alabama] or the maximum penalties shall be doubled [Idaho]) to more general instructions to consider the child witnessing to be an aggravating factor in sentencing. Some states prescribe a separate additional charge like child endangerment (n = 4), require the perpetrator to pay for counseling for child witnesses (n = 5), mandate the perpetrator to undergo counseling or an intervention program (n = 1), or require a period of supervised parenting (n = 1).

There is little published research assessing the legal treatment of IPV witnessed by children. We identified and characterized relevant laws in 31 states. Given it is more common than not for states to prescribe specific penalties to perpetrators of IPV committed in the presence of children, much could be learned about the association between these laws and health and other outcomes, such as societal and familial wellbeing. Laws aimed at protecting children from exposure to IPV might serve several purposes, including signaling the societal unacceptability of IPV in the presence of children, providing general deterrence, offering restoration and assistance to victims, and punishing or rehabilitating perpetrators. However, these laws may also carry potential harms, such as discouraging victims from disclosing violence due to fears of involvement with the child welfare system, and negatively impacting the family’s stability—socially, financially, and interpersonally—which could, in turn, increase the risk of IPV.

Outstanding questions of interest include whether laws related to child witnessing provide any of the posited intended consequences (deterrence, restoration, punishment, or rehabilitation), and furthermore whether they are associated with any specific benefits to children, such as a reduction in negative health outcomes, or with any harms. Research could examine the variations in impacts between more punitive penalties (stricter sentencing) and more restorative penalties (requirement to pay for counseling). A longitudinal legal epidemiologic study of the change in law over time (including laws no longer in effect) and changes in outcomes could assist in determining the impacts. A study examining the variation in state definitions of IPV could also be of value.

Witnessing IPV can have a range of negative effects on children across their lifetimes. Most states have laws in effect to address IPV committed in the presence of children, and most commonly these laws apply stricter sentencing to perpetrators. This paper provides a foundation for future research assessing the impacts of these laws.