Foreign STEM graduates (the acronym stands for science, technology, engineering and mathematics) can get visa extensions for three years of practical training (ie, work). Those from other disciplines are allowed only a year.
Two more years working in America means more earnings. It also means a better chance of finding an employer willing to sponsor an application for an H-1B visa, the main starting-point for skilled foreign workers who hope to settle permanently. In 2012 the Department of Homeland Security expanded the list of STEM courses. Now any reasonably crunchy economics degree can count as STEM with a tweak to its federal classification code, from economics (45.0601) to econometrics and quantitative economics (45.0603).
Economics departments appear to be catching on. Yale and Columbia have both changed the code for their economics major in the past few months; five of the eight Ivy League Universities have now done so. Students at Pennsylvania and Cornell are agitating for a switch.
Here is more from The Economist.