This Campbell systematic review assesses the effects of advocacy interventions on intimate partner violence and women's wellbeing. The review summarizes findings from 13 studies. Physical abuse: After one year, brief advocacy had no effect in two healthcare studies and one community study, but it reduced minor abuse in one antenatal care study. Another antenatal study showed reduced abuse immediately after brief advocacy, but women were also treated for depression, which may have affected results. Two studies provided weak evidence that intensive advocacy reduces physical abuse up to two years after the intervention. Sexual abuse was reported in four studies that found no effects. Emotional abuse: One antenatal care study reported reduced emotional abuse at 12 months after advocacy. Depression: Brief advocacy prevented depression in abused women attending healthcare services and pregnant women immediately after advocacy. Intensive advocacy did not reduce depression in shelter women followed up at 12 and 24 months. The moderate‐to‐low quality evidence came mostly from studies with a low risk of bias. Quality of life: Three trials of brief advocacy trials no benefit on quality of life. Intensive advocacy showed a weak benefit in two studies in domestic violence shelters/refuges, and a primary care study showed improved motivation to do daily tasks immediately after advocacy. Abstract BACKGROUND Intimate partner abuse is common worldwide, damaging the short‐ and long‐term physical, mental, and emotional health of survivors and children. Advocacy may contribute to reducing abuse, empowering women to improve their situation by providing informal counselling and support for safety planning and increasing access to different services. Advocacy may be a stand‐alone service, accepting referrals from healthcare providers, or part of a multi‐component (and possibly multi‐agency) intervention provided by service staff or others. OBJECTIVES To assess the effects of advocacy interventions within or outside healthcare settings in women who have experienced intimate partner abuse. SEARCH METHODS In April 2015, we searched CENTRAL, Ovid MEDLINE, EMBASE, and 10 other databases. We also searched WHO ICTRP, mRCT, and UK Clinical Research Network (UKCRN), and examined relevant websites and reference lists with forward citation tracking of included studies. For the original review we handsearched six key journals. We also contacted first authors of eligible papers and experts in the field. SELECTION CRITERIA Randomised or quasi‐randomised controlled trials comparing advocacy interventions for women with experience of intimate partner abuse versus no intervention or usual care (if advocacy was minimal and fewer than 20% of women received it). DATA COLLECTION AND ANALYSIS Two review authors independently assessed risk of bias and undertook data extraction. We contacted authors for missing information needed to calculate statistics for the review and looked for adverse events. MAIN RESULTS We included 13 trials involving 2141 participants aged 15 to 65 years, frequently having low socioeconomic status. The studies were quite heterogeneous in terms of methodology, study processes and design, including with regard to the duration of follow‐up (postintervention to three years), although this was not associated with differences in effect. The studies also had considerable clinical heterogeneity in relation to staff delivering advocacy; setting (community, shelter, antenatal, healthcare); advocacy intensity (from 30 minutes to 80 hours); and abuse severity. Three trials evaluated advocacy within multi‐component interventions. Eleven measured some form of abuse (eight scales), six assessed quality of life (three scales), and six measured depression (three scales). Countries and ethnic groups varied (one or more minority ethnic groups in the USA or UK, and local populations in Hong Kong and Peru). Setting was associated with intensity and duration of advocacy. Risk of bias was high in five studies, moderate in five, and low in three. The quality of evidence (considering multiple factors such as risk of bias, study size, missing data) was moderate to low for brief advocacy and very low for intensive advocacy. Incidence of abuse Physical abuse Moderate quality pooled data from two healthcare studies (moderate risk of bias) and one community study (low risk of bias), all with 12‐month follow‐up data, showed no effect on physical abuse for brief (< 12 hours) advocacy interventions (standardised mean difference (SMD) 0.00, 95% confidence interval (CI) ‐ 0.17 to 0.16; n = 558). One antenatal study (low risk of bias) showed an association between brief advocacy and reduced minor physical abuse at one year (mean difference (MD) change ‐ 1.00, 95% CI ‐ 1.82 to ‐ 0.18; n = 110). An antenatal, multi‐component study showed a greater likelihood of physical abuse ending (odds ratio (OR) 0.42, 95% CI 0.23 to 0.75) immediately after advocacy (number needed to treat (NNT) = 8); we cannot exclude impact from other components. Low to very low quality evidence from two intensive advocacy trials (12 hours plus duration) showed reduced severe physical abuse in women leaving a shelter at 24 months (OR 0.39, 95% CI 0.20 to 0.77; NNT = 8), but not at 12 or 36 months. Sexual abuse Meta‐analysis of two studies (n = 239) showed no effect of advocacy on sexual abuse (SMD ‐ 0.12, 95% CI ‐ 0.37 to 0.14), agreeing with the change score (MD ‐ 0.07, 95% CI ‐ 0.30 to 0.16) from a third study and the OR (0.96, 95% CI 0.44 to 2.12) from a fourth antenatal, multi‐component study. Emotional abuse One study in antenatal care, rated at low risk of bias, showed reduced emotional abuse at ≤ 12‐month follow‐up (MD (change score) ‐ 4.24, 95% CI ‐ 6.42 to ‐ 2.06; n = 110). Psychosocial health Quality of life Meta‐analysis of two studies (high risk of bias) showed intensive advocacy slightly improved overall quality of life of women recruited from shelters (MD 0.23, 95% CI 0.00 to 0.46; n = 343) at 12‐month follow‐up, with greater improvement in perceived physical quality of life from a primary care study (high risk of bias; MD 4.90, 95% CI 0.98 to 8.82) immediately postintervention. Depression Meta‐analysis of two studies in healthcare settings, one at high risk of bias and one at moderate risk, showed that fewer women developed depression (OR 0.31, 95% CI 0.15 to 0.65; n = 149; NNT = 4) with brief advocacy. One study at high risk of bias reported a slight reduction in depression in pregnant women immediately after the intervention (OR 0.51, 95% CI 0.20 to 1.29; n = 103; NNT = 8). There was no evidence that intensive advocacy reduced depression at ≤ 12‐month follow‐up (MD ‐ 0.14, 95% CI ‐ 0.33 to 0.05; 3 studies; n = 446) or at two years (SMD – 0.12, 95% CI – 0.36 to 0.12; 1 study; n = 265). Adverse effects Two women died, one who was murdered by her partner and one who committed suicide. No evidence links either death to study participation. AUTHORS' CONCLUSIONS Results suggest some benefits from advocacy. However, most studies were underpowered. Clinical and methodological heterogeneity largely precluded pooling of trials. Therefore, there is uncertainty about the magnitude of benefit, the impact of abuse severity, and the setting. Based on the evidence reviewed, intensive advocacy may improve short‐term quality of life and reduce physical abuse one to two years after the intervention for women recruited from domestic violence shelters or refuges. Brief advocacy may provide small short‐term mental health benefits and reduce abuse, particularly in pregnant women and for less severe abuse. Plain language summary LIMITED EVIDENCE AND LIMITED EFFECTS OF ADVOCACY TO REDUCE INTIMATE PARTNER VIOLENCE The Campbell review in brief Intensive advocacy may improve everyday life for women in domestic violence shelters/refuges and reduce physical abuse. There is no clear evidence that intensive advocacy reduces sexual, emotional, or overall abuse, or that it benefits women's mental health. It is unclear whether brief advocacy is effective. What is this review about? Partner abuse or domestic violence is common worldwide. It includes physical, emotional, and sexual abuse; threats; withholding money; causing injury; and long lasting physical and emotional health problems. Active support by trained people, which is called ‘advocacy‘, may help women make safety plans, deal with abuse, and access community resources. Advocacy may be a stand‐alone service, accepting referrals from healthcare providers, or part of a multi‐component, and possibly multi‐agency, intervention. It may take place in the community, a shelter, or as part of antenatal or other healthcare, and vary in intensity from less than an hour to 80 hours. Advocacy may contribute to reducing abuse, empowering women to improve their situation by providing informal counselling and support for safety planning and increasing access to different services. What is the aim of this review? This Campbell systematic review assesses the effects of advocacy interventions on intimate partner violence and women's wellbeing. The review summarizes findings from 13 studies. What studies are included in this review? This review summarizes evidence from 13 clinical trials comparing advocacy for 1,241 abused women with no care or usual care. Most studies followed up on the women for at least a year. Does advocacy reduce intimate partner violence and improve women's wellbeing? Physical abuse: After one year, brief advocacy had no effect in two healthcare studies and one community study, but it reduced minor abuse in one antenatal care study. Another antenatal study showed reduced abuse immediately after brief advocacy, but women were also treated for depression, which may have affected results. Two studies provided weak evidence that intensive advocacy reduces physical abuse up to two years after the intervention. Sexual abuse was reported in four studies that found no effects. Emotional abuse: One antenatal care study reported reduced emotional abuse at 12 months after advocacy. Depression: Brief advocacy prevented depression in abused women attending healthcare services and pregnant women immediately after advocacy. Intensive advocacy did not reduce depression in shelter women followed up at 12 and 24 months. The moderate‐to‐low quality evidence came mostly from studies with a low risk of bias. Quality of life: Three trials of brief advocacy trials no benefit on quality of life. Intensive advocacy showed a weak benefit in two studies in domestic violence shelters/refuges, and a primary care study showed improved motivation to do daily tasks immediately after advocacy. What do the results mean? Intensive advocacy may improve everyday life for women in domestic violence shelters/refuges in the short term and reduce physical abuse one to two years after the intervention. There is no clear evidence that intensive advocacy reduces sexual, emotional, or overall abuse, or that it benefits women's mental health. It is unclear whether brief advocacy is effective, although it may provide short‐term mental health benefits and reduce abuse, particularly in pregnant women and those suffering less severe abuse. Several studies summarised in this review are potentially biased because of weak study designs. There was little consistency between studies, with variations in the amount of advocacv given, the type of benefits measured, and the lengths of follow‐up periods, making it hard to combine their results. So it is not possible to be certain how much or which type of advocacy interventions benefit women. How up to date is this review? The search for this review was updated in April 2015, and the review published in January 2016. What is the Campbell Collaboration? The Campbell Collaboration is an international, voluntary, non‐profit research network that publishes systematic reviews. We summarise and evaluate the quality of evidence about programmes in social and behavioural sciences. Our aim is to help people make better choices and better policy decisions. About this summary This summary was prepared by Howard White (Campbell Collaboration) and is based on the Campbell Systematic Review 2016:02 ‘Advocacy interventions to reduce or eliminate violence and promote the physical and psychosocial well‐being of women who experience intimate partner abuse’ by Carol Rivas, Jean Ramsay, Laura Sadowski, Leslie L Davidson, Danielle Dunne, Sandra Eldridge, Kelsey Hegarty, Angela Taft, Gene Feder. Anne Mellbye (R‐BUP) designed the summary, which was edited and produced by Tanya Kristiansen (Campbell Collaboration).