Researcher Henriette Jansen was running a workshop in Southeast Asia on the best ways to survey women about domestic violence when one participant had an epiphany.

Interviewers in the participant's country had questioned women on their experience of domestic violence while their husbands were present, and found only 3 percent of women had ever suffered physical or sexual violence.

The figure was at odds with other surveys in the region showing that between 15 and 68 percent of women had experienced violence in their lifetimes, and the World Health Organization estimate that a third of women globally had been subjected to violence.