California and New York have approved bills to increase their state minimum wages over time to $15 an hour. Presidential candidates Hillary Clinton and Bernie Sanders favor raising the federal minimum wage. But such mandated increases do more harm than good, and they hurt the exact groups of people that policymakers say that they want to help.

Labor economist Joseph Sabia of San Diego State University summarized the academic evidence on minimum wages in this 2014 bulletin for Cato.

Sabia’s own statistical research with economist Richard Burkhauser “found no evidence that minimum wage increases were effective at reducing overall poverty rates or poverty rates among workers.” And a study by economists David Neumark and William Wascher “found that while some poor workers who kept their jobs after minimum wage increases were lifted out of poverty, others lost their jobs and fell into poverty.”

Sabia said that there are two key reasons why the minimum wage does not alleviate overall poverty the way that supporters believe that it will. The first reason is that minimum wages reduce the work available for low-skill workers:

Many firms respond to minimum wage increases by substituting away from low-skilled labor and toward other inputs. For example, grocery stores may substitute away from cashiers and toward self-checkout systems or toward higher-skilled labor. If some near-poor, low-skilled workers lose their jobs or have their hours cut as a result of minimum wage increases, then their incomes may fall, resulting in a rise in poverty among these households.

The vast majority of credible empirical evidence produced by labor economists … suggests that minimum wage increases reduce low-skilled employment. Estimates of the employment elasticity with respect to the minimum wage for low-skilled individuals generally range from -0.1 to as large as -0.3, suggesting that a 10 percent increase in the minimum wage reduces low-skilled employment by 1 to 3 percent.

The second reason that minimum wages do not alleviate poverty is that few beneficiaries of minimum wage increases live in poor households. This fact surprised me when I first read about it, but that is what the data shows. Sabia notes:

Advocates of minimum wage increases paint a vivid portrait of what they see as the typical minimum wage worker: a working single mother struggling to keep her family above the poverty line. But is this portrait accurate? Are most minimum wage workers poor or near poor?

In fact, relatively few minimum wage workers live in poor households. In a new study, Burkhauser and I examine Census data, and find that workers earning between $7.25 and $10.10 per hour—workers who would be directly affected by [a] proposed federal minimum wage increase—overwhelmingly live in non-poor households. We find that only 13 percent of workers who would be affected live in poor households, while nearly two-thirds live in households with incomes over twice the poverty line, and over 40 percent live in households with incomes over three times the poverty line. Other research suggests that poor single-female headed households make up less than 5 percent of all affected workers.

Sabia concluded his Cato bulletin: “While alleviating poverty is a widely shared goal, raising the minimum wage is unlikely to achieve that end. In reality, it is more likely to result in making many low-skilled workers worse off. The minimum wage fails to reduce net poverty because of its adverse effects on employment and poor ability to target workers living in households below the poverty threshold.”

Economist Milton Friedman said that “one of the great mistakes is to judge policies and programs by their intentions rather than their results.” Alas, that is the mistake that continues to drive the minimum wage debate in the United States.

Further analysis of the minimum wage is available here.