Doubling the numbers of toilets in slum areas can reduce sexual violence against women by almost a third, researchers have found – and now they want to prove their theory.

A team from Yale University used a mathematical model built on real-world data from Khayelitsha, in Cape Town, South Africa to show that the further women and girls have to travel to toilets that are located outside their homes – as is often the case in informal settlements around the world – the more at risk they are of sexual violence.

Cutting this travel distance down by building more toilets, the team hypothesized, would also cut down the number of sexual assaults.

Across the world, one in three women do not have access to a toilet at home, instead relying on public or community toilets. A report earlier this month highlighted the problem, calling for women to be involved in the design of toilets to minimise their exposure to harassment.

Now, Professor Gregg Gonsalves and team are appealing for funding to test out their theory. They want to build 500 to 1000 toilets in an area like Khayelitsha to see what impact it has on the rates of sexual violence.