Back in 1992, New Jersey raised the minimum wage by 18 per cent while its neighbour state, Pennsylvania, left its minimum wage unchanged. Unemployment in New Jersey should — according to mainstream economics textbooks — have increased relative to Pennsylvania. However, when economists David Card and Alan Krueger gathered information on fast food restaurants in the two states, it turned out that unemployment had actually decreased in New Jersey relative to that in Pennsylvania. Counter to mainstream demand theory we had an anomalous case of a backward-sloping supply curve.

And, of course, all those non-ideological and value-free scientific economists out there were überjoyed and prepared to revise their theories …

jp-imgresI’ve subsequently stayed away from the minimum wage literature for a number of reasons. First, it cost me a lot of friends. People that I had known for many years, for instance, some of the ones I met at my first job at the University of Chicago, became very angry or disappointed. They thought that in publishing our work we were being traitors to the cause of economics as a whole.

David Card