Last May, with considerable trepidation, I wrote an article about what seemed to be extraordinarily high rates of rape in Africa. The original data came from a study by South Africa's Medical Research Council in 2009, which found that more than a quarter of South African men - 27.6 per cent - admitted that they had committed rape. Almost half of those men had raped two or three women or girls. One in 13 had raped at least 10 victims.
Over the next couple of years, I ran across a couple of other less detailed studies suggesting that the problem was not just South African. A report from the eastern Congo in 2012 said that over a third of the men interviewed - 34 per cent - had committed rape, and an older report from Tanzania found that 20 per cent of the women interviewed said they had been raped (although only one-tenth as many rapes were reported to the police).
So I wrote a piece called "An African iceberg", in which I said that this was a phenomenon that needed urgent investigation continent-wide - but it did occur to me to wonder if there were similar icebergs in other developing countries. The only figures that were available for developing countries elsewhere were official ones, and those normally only record the number of women who tell the police they have been raped. Most don't.
Women are reluctant to report rape in any society, and in traditional societies much more so. The South African study was the only one that had adopted the strategy of asking men directly. Maybe if the same sort of study were done in other continents, I thought, it would return equally horrifying figures. And lo! Somebody else had the same thought, and the resources to do something about it.
The new report, conducted under the auspices of four United Nations agencies co-operating as "Partners for Prevention", was published last week in the online version of The Lancet Global Health, a respected British medical journal.