In this Atlantic article, James Kwak summarizes several theories on why a higher minimum wage doesn’t seem to increase unemployment in the real world as the simple supply-and-demand theory would predict.

The idea that a higher minimum wage might not increase unemployment runs directly counter to the lessons of Economics 101. According to the textbook, if labor becomes more expensive, companies buy less of it. But there are several reasons why the real world does not behave so predictably. Although the standard model predicts that employers will replace workers with machines if wages increase, additional labor-saving technologies are not available to every company at a reasonable cost. Small employers in particular have limited flexibility; at their scale, they may not be able to maintain their operations with fewer workers. (Imagine a local copy shop: No matter how fast the copy machine is, there still needs to be one person to deal with customers.) Therefore, some companies can’t lay off employees if the minimum wage is increased. At the other extreme, very large employers may have enough market power that the usual supply-and-demand model doesn’t apply to them. They can reduce the wage level by hiring fewer workers (only those willing to work for low pay), just as a monopolist can boost prices by cutting production (think of an oil cartel, for example). A minimum wage forces them to pay more, which eliminates the incentive to minimize their workforce.In the above examples, a higher minimum wage will raise labor costs. But many companies can recoup cost increases in the form of higher prices; because most of their customers are not poor, the net effect is to transfer money from higher-income to lower-income families. In addition, companies that pay more often benefit from higher employee productivity, offsetting the growth in labor costs. Justin Wolfers and Jan Zilinsky identified several reasons why higher wages boost productivity: They motivate people to work harder, they attract higher-skilled workers, and they reduce employee turnover, lowering hiring and training costs, among other things. If fewer people quit their jobs, that also reduces the number of people who are out of work at any one time because they’re looking for something better. A higher minimum wage motivates more people to enter the labor force, raising both employment and output. Finally, higher pay increases workers’ buying power. Because poor people spend a relatively large proportion of their income, a higher minimum wage can boost overall economic activity and stimulate economic growth, creating more jobs. All of these factors vastly complicate the two-dimensional diagram taught in Economics 101 and help explain why a higher minimum wage does not necessarily throw people out of work. The supply-and-demand diagram is a good conceptual starting point for thinking about the minimum wage. But on its own, it has limited predictive value in the much more complex real world.

Even if a higher minimum wage does cause some people to lose their jobs, that cost has to be balanced against the benefit of greater earnings for other low-income workers. A study by the Congressional Budget Office (CBO) estimated that a $10.10 minimum would reduce employment by 500,000 jobs but would increase incomes for most poor families, moving 900,000 people above the poverty line. Similarly, a recent paper by the economist Arindrajit Dube finds that a 10 percent raise in the minimum wage should reduce the number of families living in poverty by around 2 percent to 3 percent. The economists polled in the 2013 Chicago Booth study thought that increasing the minimum wage would be a good idea because its potential impact on employment would be outweighed by the benefits to people who were still able to find jobs. Raising the minimum wage would also reduce inequality by narrowing the pay gap between low-income and higher-income workers.