It was the curious combination of former US presidents Jimmy Carter and George H. W. Bush that first drew Carol Adelman into the fraught debate on the generosity of US giving. And it was Google that helped push her into gathering regular statistics to back up her instincts.

A former US diplomat and officer at the Agency for International Development under Ronald Reagan and Bush Sr, Adelman says she winced when Carter accused Americans at the end of the 1990s of being “stingy” in their aid to the developing world.