President Obama has called for increasing the minimum wage, saying it will help some of the poorest Americans. Opponents argue that a higher minimum wage will lead employers to cut jobs.
Figuring out the effect of raising the minimum wage is tough. Ideally you'd like to compare one universe where the minimum was raised against an alternate universe where it remained fixed.
Economist David Card found the next best thing. In 1992, New Jersey was about to raise its minimum wage.