Table 1. Summary of studies selected.

Study	Country	Sample	Design	Theory	Intervention level	Intended or actual behaviour	Focus of study	Findings
Abramsky et al. (2018)	Uganda	2,532 (45% female)	Experimental	Bystander theory	Secondary and tertiary interventions	Actual behaviour	To explore the role of community members in IPV prevention and response, both within and outside the context of a holistic community intervention.	Results show that older age, longer length of own relationship, longer time living in community, and attitudes that condemn IPV were associated with increased willingness to help.
Amar, Sutherland & Kesler (2012)	USA	202 college students (70% female; age range 18–22 years)	Experimental	Bystander theory	Secondary and tertiary interventions	Behavioural intention	This study evaluated the effectiveness and feasibility of a bystander education program that was adapted to a specific university setting.	The program increased participants confidence in how to respond to IPV situations, lowered rape myth acceptance, increased awareness of IPV as a problem, increased sense of responsibility, and increased willingness to intervene in IPV situations.
Amar, Sutherland & Laughon (2014)	USA	157 college students (53% female; age range 18–24 years)	Correlational	Bystander theory	Secondary and tertiary interventions	Behavioural intention and actual behaviour	This study compared male and female college students on rape attitudes, bystander efficacy, intention to act as a bystander, barriers to acting as a bystander, and actual use of bystander behaviours.	Gender was a significant factor for reducing rape attitudes, increasing bystander confidence, and bystander behaviours. Men had more negative rape attitudes and less bystander confidence and reported lower intention to engage in bystander behaviours. Participants were more hesitant to respond when either the survivor or perpetrator was an unknown person.
Baldry, Pacilli & Pagliaro (2015)	Italy	303 university students (50.5% female; mean age = 26.49 years, SD= 7.69)	Correlational	Moral disengagement theory	Secondary and tertiary intervention	Behavioural intention	This study focused on bystander’s reactions towards a victim of an IPV episode to try to discover whether and how a specific form of prejudice (infra-humanization) might hold toward the victim and may lead to moral disengagement resulting in decreased willingness to help the female survivor.	Participants were less willing to report an IPV episode and support the survivor when she had admitted an affair than when she had not admitted an affair. Participants attributed fewer secondary emotions to the victim when she had admitted an affair than when she had not admitted an affair. Therefore, admitting an affair with another man determined the infra-humanization of the victim. The effect of condition (admitting / not admitting; IV) on the willingness to report the IPV episode and support the victim (DV) was reduced when perceived humanness (Mediator) was entered into the equation.
Baldry & Pagliaro (2014)	Italy	218 college students (79% female; mean age = 22.5 years, SD= 4.48)	Experiment	Social identity theory	Secondary and tertiary interventions	Behavioural intention	The aim of this study was to explore what role exposure to a helping-norm (i.e., it is morally correct to intervene, call the police, help) or a not-helping-norm (i.e., belief that IPV is a private matter, not to be interfered with) has on intention to help.	When confronted with a norm that suggests that helping a victim of IPV is morally right, respondents in turn increased their reported willingness to help the victim when they strongly identified with the in-group. Importantly, evaluations of the episode of IPV did not alter the pattern of results, thus confirming that willingness to help a survivor is influenced by shared social norms.
Banyard (2008)	USA	389 college students (70% female; mean age = 19.3 years, SD= 1.2)	Correlational	Bystander theory	Secondary and tertiary interventions	Behavioural intention and actual behaviour	This study was exploratory and focussed on the development of measures of bystander attitudes and behaviour in the context of IPV. It also examined correlates of these bystander behaviours.	Results showed that being female, knowing a survivor of sexual violence, higher levels of extroversion, interpersonal and socio-political control, greater perceived sense of community, greater knowledge of information about sexual violence, and lesser rape myth acceptance were associated with more positive bystander outcomes.
Banyard & Moynihan (2011)	USA	406 college students (51.4% female; mean age = 18.7 years, SD= 1.29)	Correlational	Bystander theory	Secondary and tertiary interventions	Actual behaviour	This study aimed to increase the understanding of variability in bystander behaviour among student populations who are likely targets of prevention programs, applying the bystander framework.	Results showed that being younger, a greater sense of responsibility for ending violence, greater perceived efficacy to be an effective bystander, and having a score on the decision balance scale with pros outweighing cons, was correlated with a higher overall number of IPV related bystander intervention behaviours.
Beeble et al. (2008)	USA	6,010 adults (55% female; Mean age = 42.33 years, SD= 14.93)	Correlational	N/A	Secondary and tertiary interventions	Actual behaviour	This study aimed to identify factors that relate to individuals’ willingness to help survivors of IPV.	Results show that being female, younger, having a greater perception that IPV is a problem in the community, viewing IPV as a criminal justice issue, having prior experience of violence (i.e., witnessing violence as a child and experiencing IPV as an adult) were associated with greater willingness to intervene.
Bovill & White (2020)	UK	1,604 college students (65.5% female; age range 18–21 years).	Experimental	Bystander theory	Secondary and tertiary interventions	Actual behaviour	This study explored the relationship between awareness of IPV, confidence to intervene, and self-efficacy on positive action. Additionally, it examined if participation in a bystander intervention was associated with raised levels of awareness.	Results show that both awareness and confidence are individually and jointly significantly related to the number of positive actions, and confidence in dealing with IPV partially mediates the relationship between awareness and the number of positive actions.
Cascardi et al. (2018);	USA	556 college students (77.4% female; mean age = 20.15 years, SD= 2.98)	Correlational	Bystander theory	Secondary and tertiary interventions	Actual behaviour	The primary aims of this study were to (a) use CFA to evaluate the factor structure of the Bystander Behaviour Scale (BBS) in a sample of university undergraduates and (b) test associations between prior victimization (general and family-specific) and BBS factors.	The (1) Proactive Behaviours factor was positively associated with both general and family-specific prior victimization. The (2) Risky Situations and (3) Party Safety factors were positively associated with general prior victimization but were not associated with family-specific prior victimization. The (4) Accessing Resources factor was not associated with either general or family-specific prior victimization.
Chabot et al. (2009)	USA	71 college students (63% female; age range 18–28 years).	Correlation	Bystander theory	Secondary and tertiary interventions	Behavioural intention	This study assessed the role of situational and personal variable to understand intervention decision of informal helpers in IPV situations.	Results show that experience of child abuse, male gender of perpetrator, higher severity of abuse, and attributions of perpetrators actions to drunkenness were associated with willingness to intervene.
Cinquegrana, Baldry & Pagliaro (2018)	Italy	464 adults (66.5% female; mean age = 35.83 years; SD= 13.99)	Experimental	Attribution theory	Secondary intervention	Behavioural intention	This paper aimed to investigate the influence of contextual factors on the attribution of responsibility to female survivors of an IPV episode.	Participants attributed more responsibility to the survivor in the infidelity condition and were less willing to intervene. Participants with traditional, misogynistic, and sexually hostile gender role attitudes attributed greater responsibility to the survivor in the infidelity condition and were less willing to intervene.
Edwards & Dardis (2016)	USA	743 college students (69% female; age range 18–29 years)	Correlational	Attribution theory	Tertiary intervention	Actual behaviour	Guided by the attribution framework, this study assessed factors (i.e., situation-specific, individual, relational, attributional, and emotional response) related to positive and negative reactions from the perspective of disclosure recipients.	The following factors were associated with positive social reactions: (a) situation-specific factors: the survivor being a woman and greater frequency of IPV incidents disclosed by the victim, (b) individual factors: greater frequency of lifetime IPV incidents reported by the disclosure recipient, and less accepting attitudes toward IPV, (c) relational factors: a closer relationship with the victim and less close relationship with the perpetrator, (d) attributional: attributing less survivor responsibility, (e) emotional response factors: greater survivor empathy, and greater emotional distress experienced by the disclosure recipient at the time of disclosure.
Edwards et al. (2014)	USA	203 adults (67.4% female; mean age = 21.05 years, SD= 1.93)	Correlational	Social disorganisation theory	Secondary and tertiary interventions	Actual behaviour	This study examined the extent to which community-level poverty rates and collective efficacy was associated with individual reports of IPV perpetration, victimization, and bystander intervention.	Results showed that collective efficacy (helping norm) was positively related with bystander intervention while individual-level income status was negatively related. Community-level poverty was unrelated.
Fenton & Mott (2018)	United Kingdom	354 college students	Experimental	Bystander theory	Secondary and tertiary interventions	Behavioural intention and actual behaviour	This study aimed to provide an evaluation of the effectiveness in a student-led awareness raising campaign.	Results showed significant improvement in the desired direction in rape myth acceptance; IPV myth acceptance; bystander efficacy; readiness to help (both denial and responsibility). They showed significant improvement in the desired direction in the measure for intent to help.
Franklin, Brady & Jurek (2017)	USA	377 college students	Correlational	N/A	Secondary intervention	Behavioural intention	Aimed to explore the impact of intrapersonal characteristics, and rape- and bystander-related attitudes on direct intervention in IPV situations.	Positive bystander attitudes and violence prevention efficacy was associated with increased intention to intervene for SA. While, positive bystander attitudes, personality extroversion, and exposure to a victim were associated with increased intention to intervene for IPV.
Frye (2007)	USA	199 adults (42% female)	Correlational	N/A	Secondary intervention	Behavioural intention	This study examined factors related to predicted informal social control of IPV (i.e., intervening in such situations at the individual level).	Personal attitudes that are less tolerant of IPV, self-efficacy to respond to IPV, and being married were significantly positively associated with enacting informal social control. Whereas legal cynicism was significantly negatively associated. Additionally, none of the perceived social cohesion, visible disorder, social ties, organizational involvement, or social support factors tested were associated with predicted informal social control of IPV.
Gainsbury, Fenton & Jones (2020)	United Kingdom	83 adults (74% female; 16–73 years)	Experimental	Bystander theory	Secondary and tertiary interventions	Behavioural intention and actual behaviour	The aim was to evaluate the acceptability and potential utility of the first UK DVA bystander intervention within general communities.	There was a statistically significant change in the desired direction across Myth Acceptance (self and perception of peers), Bystander Efficacy, Behavioural Intent (self and perception of peers) and Perceived Law Knowledge at post.
La Ferle, Muralidharan & Kim (2019)	India	120 adults (42.5% female; mean age 43.77 years)	Experimental	N/A	Secondary intervention	Behavioural intention	The study explored the effectiveness of negative emotions (i.e., guilt and shame) on attitude toward an IPV ad and reporting intention of bystanders in India.	Overall, guilt and shame ads were more impactful on reporting intention than the control. Shame was more effective for individuals with an interdependent self-view and that individuals with an independent self-view were indifferent to the presence or absence of negative emotions in ads.
Latta & Goodman (2011)	USA	18 adults (89% female; age range 23–60 years)	Qualitative	Grounded theory	Secondary and tertiary interventions	Actual behaviour	This study uses grounded theory to explore in-depth network members’ subjective experience of learning about and responding to loved ones involved in IPV.	Three stages were identified as follows: 1. Becoming AwareSurvivor conditions: level of violence in relationshipMutual Conditions: helper/Survivor relationship (physical proximity; emotional closeness), level of readiness 2. Developing a narrativeSurvivor conditions: Relationship (level of violence; children; substance use; infidelity), Personal Factors (History of mental illness; History of abuse)Helper Conditions: Belief about IPV, History of abuse Mutual Conditions: helper/survivor relationship Others’ Reactions 3. Taking ActionHelper Conditions: Risk level, personal support, resource awareness, setting limits
Moynihan et al. (2011)	USA	56 female college students (mean age = 19 years)	Experimental	Bystander theory	Secondary and tertiary interventions	Behavioural intention	To assess if teaching participants how to be proactive bystanders would help increase their willingness to intervene in instances of IPV.	Results indicated that program participants showed increased bystander efficacy, confidence, responsibility for ending violence and likelihood to help. However, there were no differences between control and program in attitudes expressing denial of the problem over time.
Muralidharan & Kim (2019)	India	98 adults (52% female; mean age = 43.77 years)	Experimental	N/A	Secondary intervention	Behavioural intention	Based on SCT, this study explored whether narrative health messages might prompt bystanders to intervene when they encounter domestic violence.	It was found that narratives had a stronger impact reporting intention than non-narratives and such effects were mediated by feelings of empathy. More importantly, the mediating effects of empathy were significantly greater when bystander efficacy was low rather than high.
Muralidharan & La Ferle (2020)	India	104 adults (51.9% female; mean age = 42.37 years).	Experimental	Psychological distance	Secondary intervention	Behavioural intention	This study explored the persuasive impact of emotional ad appeals—shame (other-focused) and hope (ego-focused)—on varying levels of perceived peer support among participants from India.	The findings showed that hope was more effective than shame in generating favourable attitudes toward the ad and stronger reporting intentions. Furthermore, hope was more effective among those with low perceived peer support, while either emotion worked well for those with high perceived peer support.
Muralidharan, La Ferle & Howard (2020)	India	72 adults (36.4% female; mean age = 41 years)	Experimental	N/A	Secondary intervention	Behavioural intention	This exploratory study tested the ability of public service announcements to inspire behaviour change (i.e., to call a helpline). The current study examined the impact of self-focused emotional appeals, namely guilt (negative) and hope (positive), on varying levels of self-construal (independent vs. interdependent).	Guilt and hope were persuasive only on the independent self-construal (not interdependent). Hope (vs. guilt) significantly strengthened the intentions to call the advertised helpline for those with low independent self-construal. While, both hope and guilt were found to be equally effective on the high independent self-construal.
Pagliaro et al. (2021)	Italy	110 adults (73% female; mean age 34.07 years, SD= 12.97)	Correlational	Attribution theory	Tertiary intervention	Behavioural intention	This article examined indirect consequences for the survivors of IPV in terms of ostracism, reputational threats, and reduced help.	Results show that survivors of IPV (vs. generic violence) received a more negative moral evaluation and considered as more responsible for the violence which was associated with less willingness to approach and defend the survivor or include her in relevant ingroups 1 year later.
Rai (2020)	USA	468 adults (56% female; ages range 18–35 years)	Correlational	Intersectionality theory	Tertiary intervention	Behavioural intention	This study aimed to explore the correlates of recommending a help-seeking resource to a survivor of IPV among the US South Asian community.	Women were more likely to recommend a help-seeking resource than men. However, Individuals who were religious, from a joint family (versus a nuclear family), and those with conservative gender role attitudes had a lesser likelihood of recommending a help seeking resource.
Riley & Yamawaki (2018)	USA	184 college students (59% female; mean age = 20.59 years)	Experimental	N/A	Tertiary intervention	Behavioural intention	This study explored factors that predict an informal supporter’s intentions to help a female IPV survivor in a heterosexual relationship and factors related to victim blaming. Specifically, the effects of Right-Wing Authoritarianism, Benevolent Sexism, and Hostile Sexism, on intentions to help an IPV survivor were investigated.	Participants with higher scores on RWA, BS, HS, those who had the “stay” condition (survivor remained in the violent relationship) and men where all less likely to offer helpful support the victim. Participants with higher scores on RWA, BS, and HS were more likely to respond to survivors in unhelpful ways (e.g., insist that the victim attend couples counselling, advise the survivor she should not make her husband angry).
Storer, McCleary & Hamby (2021)	USA	39 emerging adults (49% female; age range 17–22)	Qualitative	Situational cognitive model of adolescent bystander behaviour	Secondary intervention	Behavioural intention	The purpose of this exploratory study was to investigate emerging adults’ willingness to use bystander behaviours in response to witnessing dating and community violence.	Barriers to intervening were a perception that intervening is dangerous/ snitching, perceived injunctive norms about intervening (i.e., you should “mind your business”), perceived inability to effect change, and struggling “to get it all together” (feel unable to help as they cannot cope with their own stress/struggles). While factors influencing Intervention were the perceived seriousness of the incident, witnessing male-perpetrated forms of dating abuse, relationship to the target or perpetrator of abuse.
Waterman et al. (2021)	USA	899 college students (70.6% female; mean age = 19.5 years, SD= 1.2 years)	Correlational	Theory of planned behaviour	Tertiary intervention	Actual behaviour	This paper aimed to examine the association between disclosure recipients anticipated and actual responses to IPV.	Participants who anticipated a higher likelihood of providing negative and positive reactions tended to give those reactions more frequently during a subsequent disclosure. There were also significant positive associations between anticipated and actual victim responsibility, empathy, confusion, and ineffectiveness.
Weitzman, Cowan & Walsh (2020)	USA	1,307 nationally representative adults aged over 15 years	Correlational	Bystander theory	Secondary and tertiary interventions	Actual behaviour	This article investigated the perceived barriers to intervening in IPV.	The study found that fear of physical injury, not wanting to intervene in private matters and fear of misinterpreting the situation were associated with reduced help-giving intention.
Woods et al. (2020)	USA	393 college students (79.7% female; mean age = 19.02 years, SD= 2.86)	Correlational	Bystander theory	Secondary and tertiary interventions	Actual behaviour	This study aimed to consider how personal history of recent physical, sexual, and psychological victimisation interacted with likelihood to intervene.	Survivors of psychological aggression were significantly more likely to intervene in low-risk, high-risk, and post-event situations. Survivors of physical and sexual violence were more likely to intervene in low-risk situations.