From Thomas Sowell’s book “Basic Economics: A Common Sense Guide to the Economy"
Minimum wage laws make it illegal to pay less than the government-specified price for labor. By the simplest and most basic economics, a price artificially raised tends to cause more to be supplied and less to be demanded than when prices are left to be determined by supply and demand in a free market. The result is a surplus, whether the price that is set artificially high is that of farm produce or labor.Making it illegal to pay less than a given amount does not make a worker’s productivity worth that amount—and, if it is not, that worker is unlikely to be employed. Yet minimum wage laws are almost always discussed politically in terms of the benefits they confer on workers receiving those wages. Unfortunately, the real minimum wage is always zero, regardless of the laws, and that is the wage that many workers receive in the wake of the creation or escalation of a government-mandated minimum wage, because they either lose their jobs or fail to find jobs when they enter the labor force.
(via Mark Perry)