THE PARTNER ABUSE STATE OF KNOWLEDGE PROJECT

Courtesy of the scholarly journal Partner Abuse and the Association of Domestic Violence Intervention Providers.

About the project

Over the years, research on partner abuse has become unnecessarily fragmented and politicised. The purpose of The Partner Abuse State of Knowledge Project (PASK) is to bring together — in a rigorously evidence-based, transparent and methodical manner — existing knowledge about partner abuse with reliable, up-to-date research that can easily be accessed by both researchers and the general public.

Family violence scholars from the United States, Canada and the U.K. were invited to conduct an extensive and thorough review of the empirical literature across 17 broad topic areas. They were asked to conduct a formal search for published, peer-reviewed studies through standard, widely-used search programs, and then catalogue and summarise all known research studies relevant to each major topic and its sub-topics.

In the interest of thoroughness and transparency, the researchers agreed to summarise all quantitative studies published in peer-reviewed journals after 1990, as well as any major studies published prior to that time, and to clearly specify exclusion criteria. Included studies are organised in extended tables, each containing summaries of studies relevant to a particular sub-topic.

In this unprecedented undertaking, 42 scholars and 70 research assistants at 20 universities and research institutions spent two years or more researching their topics and writing the results. Approximately 12,000 studies were considered and more than 1,700 were summarised and organised into tables. The 17 manuscripts appear in 5 consecutive special issues of the peer-reviewed journal Partner Abuse — a total of 2,657 pages. All conclusions, including the extent to which the research evidence supports or undermines current theories, are based strictly on the data collected.

More information is available at domesticviolenceresearch.org.

Prevalence of partner abuse

Victimisation

• Overall, 22% of individuals are assaulted by a partner at least once in their lifetime (23% for females and 19.3% for males)
• Higher overall rates among dating students
• Higher victimisation for male than female high school students
• Lifetime rates higher among women than men
• Past year rates somewhat higher among men
• Higher rates of intimate partner violence (IPV) among younger, dating populations "highlights the need for school-based IPV prevention and intervention efforts"

Perpetration

• Overall, 25.3% of individuals have perpetrated IPV
• Rates of female-perpetrated violence higher than male-perpetrated (28.3% vs. 21.6%)
• Wide range in perpetration rates: 1.0% to 61.6% for males; 2.4% to 68.9% for women
• Range of findings due to variety of samples and operational definitions of PV

Emotional abuse and control

• 80% of individuals have perpetrated emotional abuse
• Emotional abuse categorised as either expressive (in response to a provocation) or coercive (intended to monitor, control and/or threaten)
• Across studies, 40% of women and 32% of men reported expressive abuse; 41% of women and 43% of men reported coercive abuse
• According to national samples, 0.2% of men and 4.5% of women have been forced to have sexual intercourse by a partner
• 4.1% to 8% of women and 0.5% to 2% of men report at least one incident of stalking during their lifetime
• Intimate stalkers comprise somewhere between one-third and one-half of all stalkers
• Within studies of stalking and obsessive behaviours, gender differences are much less when all types of obsessive pursuit behaviours are considered, but more skewed toward female victims when the focus is on physical stalking

Context of partner abuse

Bi-directional vs. uni-directional

• Among large population samples, 57.9% of IPV reported was bi-directional and 42% unidirectional; 13.8% of the unidirectional violence was male to female (MFPV), 28.3% was female to male (FMPV)
• Among school and college samples, bidirectional violence was 51.9%; 16.2% MFPV and 31.9% FMPV
• Among respondents reporting IPV in legal or female-oriented clinical/treatment seeking samples not associated with the military, 72.3% was bi-directional; 13.3% MFPV, 14.4% FMPV
• Within military and male treatment samples, only 39% of IPV was bi-directional; 43.4% MFPV and 17.3% FMPV
• Unweighted rates: bidirectional rates ranged from 49.2% (legal/female treatment) to 69.7% (legal/male treatment)
• Extent of bi-directionality in IPV comparable between heterosexual and LGBT populations
• 50.9% of IPV among Whites bilateral; 49% among Latinos; 61.8% among African-Americans

Motivation

• Male and female IPV perpetrated from similar motives — primarily to get back at a partner for emotionally hurting them, because of stress or jealousy, to express anger and other feelings that they could not put into words, and to get their partner's attention
• Eight studies directly compared men and women on the power/control motive. Three reported no significant gender differences and one had mixed findings. One paper found women were more motivated by power/control than men, and three found men were more motivated; gender differences were weak
• Of ten papers containing gender-specific statistical analyses, five indicated that women were significantly more likely than men to report self-defense as a motive. Four papers did not find statistically significant gender differences, and one paper reported that men were more likely to report this motive. Authors point out that it might be particularly difficult for highly masculine males to admit to perpetrating violence in self-defense, as it implies vulnerability
• Self-defense was endorsed in most samples by only a minority of respondents, male and female. For non-perpetrator samples, rates ranged from 0% to 21% for men, and 5% to 35% for women. The highest rates (50% for men, 65.4% for women) came from perpetrator samples, who may have reasons to overestimate this motive
• None of the studies reported anger/retaliation as significantly more of a motive for men than women; two papers indicated anger was more likely a motive for women's violence
• Jealousy/partner cheating seems to be a motive for both men and women

Risk factors

• Demographic risk factors predictive of IPV: younger age, low income/unemployment, minority group membership
• Low to moderate correlations between childhood-of-origin exposure to abuse and IPV
• Protective factors against dating violence: positive, involved parenting during adolescence; encouragement of nonviolent behaviour; supportive peers
• Negative peer involvement predictive of teen dating violence
• Conduct disorder/anti-social personality are risk factors for IPV
• Weak association between depression and IPV, strongest for women
• Weak association overall between alcohol and IPV, but stronger for drug use
• Alcohol use more strongly associated with female-perpetrated than male-perpetrated IPV
• Married couples at lower risk than dating couples; separated women the most vulnerable
• Low relationship satisfaction and high conflict predictive of IPV, especially high conflict
• With few exceptions, IPV risk factors the same for men and women

Impact on victims, children and families

Impact on partners

• Victims of physical abuse experience more physical injuries, poorer physical functioning and health outcomes, higher rates of psychological symptoms and disorders, and poorer cognitive functioning compared to non-victims. These findings were consistent regardless of the sample and, with some exceptions, were generally greater for female victims compared to male victims
• Physical abuse significantly decreases female victims' psychological well-being; increases the probability of depression, anxiety, PTSD and substance abuse; victimised women are more likely to visit mental health professionals and to take medications including painkillers and tranquillisers
• Few studies have examined the consequences of physical victimisation in men, and those that have focused primarily on sex differences in injury rates
• When severe aggression has been perpetrated (e.g., punching, kicking, using a weapon), rates of injury are much higher among female victims, and those injuries are more likely to be life-threatening and require a hospital visit. However, when mild-to-moderate aggression is perpetrated (e.g., shoving, pushing, slapping), men and women tend to report similar rates of injury
• Physically abused women engage in poorer health behaviours and risky sexual behaviours. They are more likely to miss work, have fewer social and emotional support networks, and are less likely to care for their children and perform household duties
• Psychological victimisation among women is significantly associated with poorer occupational and social functioning
• Psychological victimisation is strongly associated with symptoms of depression and suicidal ideation, anxiety, self-reported fear and increased perceived stress, insomnia and poor self-esteem
• Psychological victimisation is at least as strongly related as physical victimisation to depression, PTSD, and alcohol use, and these effects remain even after accounting for physical victimisation
• Because research on the psychological consequences of abuse on male victims is limited and has yielded mixed findings, it is premature to draw firm conclusions

Effects on children

• Significant correlation between witnessing mutual PV and both internalising (e.g., anxiety, depression) and externalising outcomes (e.g., school problems, aggression) for children and adolescents
• Exposure to male-perpetrated PV: worse outcomes in internalising and externalising problems, including higher rates of aggression toward family members and dating partners
• Children and teens exposed to female-perpetrated PV are significantly more likely to aggress against peers, family members and dating partners
• Results mixed regarding additive effect of exposure to PV and experiencing direct child abuse
• Witnessing PV in childhood correlated with trauma symptoms and depression in adulthood
• Child abuse correlated with family violence perpetration in adulthood
• Children more impacted by exposure to conflict characterised by contempt, hostility and withdrawal, compared to that characterised only by anger
• Greater impact when the topic discussed concerns the child (e.g., disagreements over child rearing, blaming the child)
• High inter-parental conflict/emotional abuse leads to a decrease in parental sensitivity, warmth and consistent discipline; and an increase in harsh discipline and psychological control
• Neurobiological and physical functioning mediate the relationship between inter-parental conflict and negative child outcomes
• Maternal behaviours somewhat more affected than paternal behaviours, though findings are equivocal
• Greater effects found for mother–child relationships and child outcomes through the toddler years; greater effects for father–child relationships during the school-age years
• Family systems theory useful in understanding how discord in one part of the family can impact functioning in the family as a whole

Partner abuse in other populations

Ethnic minority and LGBT populations

• African-Americans: older studies found higher rates of male-to-female partner violence (MFPV); recent studies have found higher rates of female-to-male partner violence (FMPV)
• Psychological aggression reported at significantly higher rates than physical aggression
• As with White populations, minor/moderate aggression far more prevalent among Black couples than severe aggression
• In dating studies, no gender differences in rates of physical or psychological victimisation, but women reported higher rates of physical aggression than men
• Latinos: mutual and minor/moderate PV most prevalent, but not as much as psychological aggression
• No gender differences for physical or psychological aggression, except among migrant farm workers where MFPV was highest
• Asian Americans: the one general population study found mutual violence perpetration to be one-third of total
• Overall rates of PV comparable across gender in large population, community and dating samples
• Lowest rates found among Vietnamese, compared to Filipino, Chinese or others of Asian descent
• Native Americans: only three studies found; women reported higher rates of victimisation than men, and higher levels of injuries
• Risk factors for ethnic minority PV include substance abuse, low SES, and violence exposure and victimisation in childhood
• LGBT populations: higher overall rates compared to heterosexual populations
• Inconsistent findings regarding PV differences between same-sex subgroups
• Risk factors for LGBT groups include discrimination and internalised homophobia

Partner abuse worldwide

• A total of 162 articles reporting on over 200 studies met the inclusion criteria and were summarised in the online tables for Asia, the Middle East, Africa, Latin America and the Caribbean, and Europe and the Caucasus
• 40 articles (73 studies) in 49 countries contained data on both male and female IPV, with a total of 117 direct comparisons across gender for physical PV
• Rates of physical PV were higher for female perpetration / male victimisation compared to male perpetration / female victimisation, or were the same, in 73 of those comparisons (62%)
• 54 comparisons were made for psychological abuse including controlling behaviours and dominance, with higher rates for female perpetration / male victimisation in 36 comparisons (67%)
• Of 19 direct comparisons for sexual PV, rates were higher for female perpetration / male victimisation in 7 comparisons (37%)
• When only adult samples from large population and community surveys were considered, the overall percentage of partner abuse higher for female perpetration / male victimisation, or the same, was 44% for adult IPV
• Studies reporting on female victimisation only found the lowest rates for physical abuse victimisation in a large population study in Georgia (2%, past year), and the highest in a community survey in Ethiopia (72.5% past year). Rates of physical PV in some regions far exceed the average found in the United States
• Lowest rates of psychological victimisation were found in a large population study in Haiti (10.8% past year); highest was 98.7% in Bangkok, Thailand (past year)
• Unlike physical IPV, the highest rates of psychological abuse throughout the world are about the same as those found in the United States (80%)
• Rates of sexual abuse victimisation differed widely across regions, from 1% in Georgia (past year) to 68% among secondary school students in Ethiopia (lifetime)
• Physical injuries were compared across gender in two studies. As expected, abused women were found to experience higher rates of physical injuries compared to men
• More frequently mentioned were the psychological and behavioural effects of abuse: PTSD symptomology, stress, depression, irritability, shame and guilt, poor self-esteem, flashbacks, sexual dissatisfaction and unwanted sexual behaviour, changes in eating behaviour, and aggression
• Two studies compared mental health symptoms across gender. In Botswana, women evidenced significantly more of these than men; a clinical study in Pakistan found male and female IPV victims suffered equally (60% depression, 67% anxiety)
• A variety of health-related outcomes were associated with IPV victimisation, including poor physical health, more long-term illnesses, more prescribed drugs, STDs, and disturbed sleep. Abused mothers experienced poorer reproductive health, respiratory infections, induced abortion and complications during pregnancy
• The most common risk factors found in this review of IPV in Asia, Africa, the Middle East, Latin America and Europe have also been found significant in the U.S. and other English-speaking industrialised nations
• Most often cited: low household income and victim/perpetrator unemployment (36 studies). Almost as high: victim's low education level (35). Alcohol and substance abuse by the perpetrator (26). Family-of-origin abuse, whether directly experienced or witnessed (18). Victim's younger age (17). Perpetrator's low education level (16)
• In contrast to the U.S., there is a much higher tolerance by both men and women for IPV in other parts of the world, with rates of approval depending on the country and the type of justification
• Regression analyses indicated that a country's level of human development (HDI) was not a significant predictor of male or female physical partner abuse perpetration
• Additional regression analyses indicated that a nation's gender inequality level (GII) was not predictive of either male or female perpetrated physical partner abuse, or female-only victimisation, in general population or community samples
• Separate regression analyses on IDVS dating samples indicate that higher gender inequality levels significantly predict higher prevalence of male and female physical partner abuse perpetration. GII level explained the variance for 17% of male partner abuse and 19% of female partner abuse perpetration
• A final analysis examined the association between dominance by one partner and partner violence in dating samples using IDVS data. Male dominance scores were not found to be predictive of male partner violence perpetration; however, female dominance scores explained 47% of the variance of female partner violence perpetration

Law enforcement and the criminal justice system

The crime control effects of criminal sanctions

• Possible causal mechanisms for the effectiveness of arrest and prosecution: fear of sanctions and victim empowerment. Because none of the reviewed studies adequately measure such mechanisms, the review assumes a general crime control effect that is neutral about causal mechanisms

• Wide range of recidivism from 3.1% to 65.5%, due to high variability in measures of repeat offending (e.g., follow-up time frame)
• Studies unclear about the exact nature of the sentence imposed, and what constitutes a "prosecution" or "conviction"
• Diversity of analytic methods hinders analysis of effect sizes
• Sample selection bias: none of the studies address this issue; for instance, if a small number of low-risk cases are prosecuted, prosecuted offenders are more likely to re-offend compared to those not prosecuted, because of the selection process
• Missing data often leads to cases being dropped from a study, which in turn creates sample bias

Gender and racial/ethnic differences in criminal justice decision-making

• Female arrests affected by high SES, presence of weapons and witnesses
• Women more likely than men to be cited rather than taken into custody, but the gender discrepancy narrows when deciding whether to file charges as misdemeanours or felonies
• Men are more likely than women to be convicted and to be given harsher sentences

• No conclusive evidence of discrimination against ethnic minority groups in either arrest, prosecution or sentencing
• Dual arrests were more likely in same-sex couples compared to heterosexual couples, perhaps due to incorrect assumption by police that same-sex couples more likely to engage in mutual violence
• Protective orders far more likely to be granted, and with more restrictions, to women than to men (particularly in cases involving less severe abuse histories)
• Mock juries more likely to assign blame responsibility to male perpetrators in contrast to female perpetrators, even when presented with identical scenarios

Effectiveness of protective orders

• A large percentage of women who are issued protective orders (POs) tend to be unemployed or under-employed, with income between $10,000 and $15,000; almost 50% are financially dependent on their partners
• At least half of women obtaining POs are married; married women are more likely to stay with their abusers and be pregnant
• Women who are issued POs tend to have more mental health issues (depression, PTSD); rural women tend to experience more abuse and mental health issues than urban women
• Only a few studies have examined characteristics of men seeking a PO
• "Effectiveness" defined as violations of protective orders and/or re-victimisation
• Some studies have found POs to reduce violence against victims, with an almost 80% reduction in violence reported to police
• Victims report feeling safer and having greater psychological well-being after obtaining a protective order; still, POs are violated at a rate of between 44% and 70%
• Nearly 60% of women who had secured a PO reported to have subsequently been stalked
• Severity of criminal charges on the offender, as well as previous violations, are the best predictors of new PO violations
• Although there is no significant difference in the amount of abuse suffered by married and unmarried victims, married victims are less likely to seek final protective orders, perhaps because they are more likely to be re-victimised
• Women granted POs at significantly higher rates than men, especially in cases involving lower level violence
• No gender differences in the enforcement of POs, and no differences in rates of recidivism

Assessment and treatment

Risk assessment

• Little agreement in the literature with regard to the most appropriate approach (actuarial, structured clinical judgment) nor which specific measure has the strongest empirical validation behind it, leaving clinicians and policy makers with little clear guidance
• Review yielded studies reporting on the validity and reliability of eight IPV-specific actuarial instruments and three general actuarial risk assessment measures
• Range of AUC values reported for the validity of the Ontario Domestic Assault Risk Assessment (ODARA) predicting recidivism was good to excellent (0.64–0.77)
• The single study that reported on the Domestic Violence Risk Appraisal Guide (DVRAG) reported an AUC = 0.70 (p < .001). The inter-rater reliability for both instruments was excellent
• The Domestic Violence Screening Inventory (DVSI) and DVSI–Revised were found to be good predictors of new family violence incidents and IPV recurrence (AUC range 0.61–0.71)
• Three studies examined the Psychopathy Checklist – Revised (PCL-R) and Violence Risk Appraisal Guide (VRAG), reporting AUCs ranging from 0.66–0.71 and 0.67–0.75 respectively
• The Level of Service Inventory – Revised (LSI-R) and LSI – Ontario Revision (LSI-OR) were discussed in four articles, reporting two AUC values of 0.50 and 0.73, both predicting IPV recidivism
• Two structured professional judgment instruments were included: the Spousal Assault Risk Assessment (SARA) and the Brief Spousal Assault Form for the Evaluation of Risk (B-SAFER). SARA research reports nine AUCs ranging from 0.52–0.65. Interrater reliability was excellent for total scores, good for summary risk ratings, and poor for critical items
• The Danger Assessment (DA) has the largest body of literature behind it, but limitations in the research inhibit a clear determination of the psychometric properties. Victim appraisals of the risk of future IPV show some evidence of predictive accuracy; further research is needed
• Overall, the literature reveals moderate postdictive/predictive accuracy across measures, with little evidence to support one as being highly superior to others
• Based on the available literature, we are unable to provide guidance on the clinical relevance and utility of these instruments with female perpetrators, male victims, and in same-sex relationships due to the lack of studies using relevant populations

Effectiveness of primary prevention efforts

• All studies incorporated a curriculum-based intervention, with the primary goal of lowering rates of PV
• Schools provided the setting for two-thirds of the interventions; the rest were conducted in community settings
• Of the five most methodologically-sound school based studies, only one — the Safe Dates Program — found a clear-cut positive outcome on PV behaviour (emotional abuse, mild physical abuse and sexual coercion)
• In contrast, each of the five most methodologically-sound community-based studies was deemed effective in reducing PV; among them were two interventions targeting couples and one family-based intervention involving parents and their adolescent children
• Although outcomes are mixed, especially for the school-based studies, and no studies were replicated, the authors suggest that "because prevention is generally cost-effective, programming is badly needed to prevent IPV before it begins"

Effectiveness of intervention programs for perpetrators and victims

• Reviewed studies all utilised either a randomised or quasi-experimental design
• Mixed evidence for the effectiveness of perpetrator interventions
• Evidence that group or couples format can be effective, but many studies flawed
• More promising results for programs with alternative content (e.g., programs that encourage a strong therapist–client relationship and group cohesion, use some form of Motivational Interviewing technique)
• Inconsistent effects for brief interventions
• Structured interventions found to reduce rates of re-victimisation compared to no-treatment controls when they include supportive advocacy
• Cognitive-behavioural treatment (CBT) most effective in reducing the deleterious effects of PV on victims and enhancing their emotional functioning
• Little evidence to indicate the superiority of one type of intervention over another. There is no empirical justification for agencies, state organisations, judges, mental health professionals, or others to limit the type of services offered to clients, or to restrict the theoretical and ideological underpinnings of such methods.

John Hamel, LCSW conceived and supervised the project. The journal's former Associate Editors, Jennifer Langhinrichsen-Rohling, Ph.D., and Denise Hines, Ph.D., provided editorial assistance.

Full references for PASK manuscripts

• Capaldi, D.M., Knoble, N.B., Shortt, J.W., & Kim, H.K. (2012). A systematic review of risk factors for intimate partner violence. Partner Abuse, 3(2), 231–280.
• Carney, M., & Barner, J. (2012). Prevalence of partner abuse: Rates of emotional abuse and control. Partner Abuse, 3(3), 286–335.
• Desmarais, S.L., Reeves, K.A., Nicholls, T.L., Telford, R. & Fiebert, M.S. (2012). Prevalence of physical violence in intimate relationships – Part 1: Rates of male and female victimization. Partner Abuse, 3(2), 140–169.
• Desmarais, S.L., Reeves, K.A., Nicholls, T.L., Telford, R. & Fiebert, M.S. (2012). Prevalence of physical violence in intimate relationships – Part 2: Rates of male and female perpetration. Partner Abuse, 3(2), 170–198.
• Eckhardt, C.I., Murphy, C.M., Whitaker, D.J., Sprunger, J., Dykstra, R., & Woodard, K. (2013). The effectiveness of intervention programs for perpetrators and victims of intimate partner violence. Partner Abuse, 4(2).
• Langhinrichsen-Rohling, J., & McCullars, A. (2012). Motivations for men and women's intimate partner violence perpetration: A comprehensive review. Partner Abuse, 3(4).
• Langhinrichsen-Rohling, J., Misra, T.A., Selwyn, C. & Rohling, M.L. (2012). Rates of bi-directional versus unidirectional intimate partner violence across samples, sexual orientations, and race/ethnicities: A comprehensive review. Partner Abuse, 3(2), 199–230.
• Lawrence, E., Oringo, A., & Brock, R. (2012). The impact of partner abuse on partners. Partner Abuse, 3(4).
• MacDonnel, K. Watson (2012). The combined and independent impact of witnessed interparental violence and child maltreatment. Partner Abuse, 3(3), 358–378.
• Maxwell, C., & Garner, J. (2012). The crime control effects of criminal sanctions for intimate partner violence. Partner Abuse, 3(4).
• Nicholls, T., Pritchard, M., Reeves, K., & Hilterman, E. (2013). Risk assessment in intimate partner violence: A review of contemporary approaches. Partner Abuse, 4(1).
• Russell, B. (2012). Effectiveness, victim safety, characteristics and enforcement of protective orders. Partner Abuse, 3(4).
• Santovena, E., Lambert, T., & Hamel, J. (2013). Partner abuse worldwide. Partner Abuse, 4(1).
• Shernock, S., & Russell, B. (2012). Gender and racial/ethnic differences in criminal justice decision making in intimate partner violence cases. Partner Abuse, 3(4).
• Sturge-Apple, M.L., Skibo, M.A., & Davies, P.T. (2012). Impact of parental conflict and emotional abuse on children and families. Partner Abuse, 3(3), 379–400.
• West, C. (2012). Partner abuse in ethnic minority and gay, lesbian, bisexual, and transgender populations. Partner Abuse, 3(3), 336–357.
• Whitaker, D.J., Murphy, C.M., Eckhardt, C.I., Hodges, A.E., & Cowart, M. (2013). Effectiveness of primary prevention efforts for intimate partner violence. Partner Abuse, 4(2).