Students from various colleges holding placards as they shout slogans during rally against gender discrimination and violence towards women in Mumbai December 10, 2014. (Shailesh Andrade/Reuters)

Mary Ellsberg is the director of the Global Women’s Institute at George Washington University.

When violence is inflicted upon women and girls, we rightly think of it as a crime and a tragedy. But we should also recognize it for what it truly is: a global pandemic and a public health crisis.

The World Health Organization estimates that more than 30 percent of the world’s women have suffered physical or sexual abuse by a partner. Between 100 and 140 million girls and women have undergone female genital mutilation. More than 60 million women between ages 20 and 24 were married before their 18th birthdays, many of them forced.

Violence affects women everywhere, regardless of their culture or socioeconomic status. It is a persistent, substantial barrier to the health and development of its victims, their families and their communities. Despite increased worldwide attention to these widespread human rights abuses, and recent advances in knowledge about how to tackle them, levels of violence against women remain unacceptably high.

We need to act as we would in the face of any other epidemic — by responding appropriately to victims and moving swiftly to implement preventive measures. But what, exactly, works?

This question led us at George Washington University’s Global Women’s Institute to conduct a review of interventions intended to prevent or reduce violence against women. We scrutinized more than 100 studies conducted in every corner of the globe — from the richest to the poorest countries — and reached out to more than 30 experts to identify studies we might have missed. These findings were published in November in the Lancet.

What did we learn? The good news is that violence against women and girls can be prevented. The most effective programs are, not surprisingly, the most ambitious. They typically involved entire communities — women, girls, men and boys of all ages and backgrounds — working in concert to challenge attitudes and behaviors. These interventions facilitated communication, conflict resolution and nonviolent actions and often integrated microfinance, education and social protection initiatives into their efforts.

For example, successful programs in Uganda and Kenya empowered adolescent girls through training in life and vocational skills and self-defense. The girls who participated in the program showed substantial improvements in knowledge of sexual and reproductive health and reported large reductions in coerced sex as compared with a control group; in Kenya, sexual assaults decreased by 60 percent. In Kampala, Uganda, the SASA! program trains local activists to use informal mechanisms such as theater, door-to-door conversations, games and posters to engage their neighbors, friends and peer groups in dialogue about men’s use of power and violence over women. After two years, a randomized trial showed a 52 percent reduction of physical partner violence against women.

In another randomized trial, women in rural South Africa were provided with microfinance opportunities and skill-building sessions on HIV, challenging social norms around gender, communications and addressing violence. After two years, the trial showed a 55 percent reduction in reports of physical or sexual partner violence. This model is being scaled up in South Africa and expanded to Tanzania and Peru.

Ultimately, what is clear is that interventions that are comprehensive show the most promise and that investment in these programs can make a difference. But we also discovered that much of the existing research is, unfortunately, still quite limited and largely inconclusive. The evidence for the most effective interventions is highly skewed toward high-income countries. The United States alone accounted for two-thirds of the studies. Furthermore, these countries focus much more on responses to violence, rather than prevention. Although many countries have made substantial progress toward criminalizing violence against women, the laws on the books often do not receive the enforcement funding they need to be truly effective. Many women and girls continue to suffer discrimination, experience violence and lack access to vital health and legal services.

There are immediate steps that governing bodies can take to move forward. In the United States, Congress could pass the International Violence Against Women Act, which would ensure that U.S. foreign policy supports best practices to reduce and prevent gender-based violence. In addition, the United Nations should include in its post-2015 Sustainable Development Goals a target on the reduction of violence against women and girls. Moreover, governments worldwide must be persuaded to accept the fact that violence against women and girls is a barrier to their development and allocate the necessary resources to prevention, as well as change laws, policies and institutions that perpetuate gender inequality and foster violence.

Finally, we must understand that, like any effort to solve a massive global health crisis, more rigorous research is needed to determine what works best in a variety of situations. Not one grand vaccine will ever eradicate violence against women — just the hard work of transforming deeply entrenched societal norms, one community at a time.