 A 2014 survey of the existing literature on emigration finds that a 10 percent emigrant supply shock would increase wages in the sending country by 2–5.5%.According to economists Michael Clemens and Lant Pratchett, "permitting people to move from low-productivity places to high-productivity places appears to be by far the most efficient generalized policy tool, at the margin, for poverty reduction".A successful two-year in situ anti-poverty program, for instance, helps poor people make in a year what is the equivalent of working one day in the developed world.