Financial Times columnist Martin Wolf has called for an international blue-ribbon commission on migration. CGD research fellow Michael Clemens endorses the idea--and agrees with Wolf that the lack of data hinders efforts to understand the development impact of migration. While most countries track migrant arrivals, very few provide detailed public counts of migrant departures. Clemens says this is like reporting imports but not exports. He adds that CGD will convene an experts' group on migration statistics in 2008 to identify ways of addressing this knowledge short-fall.