There have been dozens of articles in the academic literature on the impact of the minimum wage on employment, particularly on the employment of low-skilled workers. Virtually every one of these articles finds that an increase in the minimum wage reduces employment. As Don points out, this is just one of the negative impacts of the minimum wage. There are other effects that are harder to observe and measure—on the job training, the expected level of effort to be put forth on the job and so on.
Economists have done an immense amount of work trying to measure these effects and the overall impact on the poor. The overwhelming consensus has been that minimum wages serve the poor very poorly. The standard finding is that a 10% increase in the minimum wage reduces employment among low-skilled workers from 1% to 3%.
This consensus was challenged in 1993 in a series of papers by Card and Krueger. Using a very different methodology from previous research, they found virtually no effect on employment and some evidence that an increase in the minimum wage might increase employment among low-skilled workers. Card and Krueger’s work generated a critical response questioning the reliability of their findings.
I do not find the Card and Krueger findings compelling. Some do.
Even if you don’t, you can still think it a good idea to put 1% or 3% of low-skilled workers out of work in return for a 10% increase in the wage of those who keep their jobs. Personally, I find that to be a very unattractive trade-off, especially when you consider the non-employment effects, but that is a judgment call.