United States of low wages
John Schmitt [pdf] defines low-wage jobs as paying less than two-thirds of the national median hourly wage.
Schmitt also explains that low wages are not the only problem for low-wage workers, particularly in the United States:
The intense policy focus on low pay can obscure the reality that low pay is often among the least of the labor-market problems facing low-wage workers, especially in the United States. U.S. labor law offers workers remarkably few protections. U.S. workers, for example, have the lowest level of employment security in the OECD and no legal right to paid vacations, paid sick days, or paid parental leave. The low level of union coverage in the United States means that contractual obligations generally don’t make up for the lack of legal guarantees.
In the absence of legal or contractual rights, low-wage workers are the least likely to have access to core benefits. Almost half of private-sector workers in the bottom fourth of the wage distribution in 2010, for example, had no paid vacations. In the same year, about 68 percent of private-sector workers in the bottom fourth of the wage distribution had no paid sick days, compared to only about 11 percent of workers in the top fourth. In the U.S. context, however, probably the most critical problem facing low-wage workers is the lack of access to health care. Rho and Schmitt estimate that in 2008, more than half (54 percent) of workers in the bottom wage quintile did not have employer-provided health insurance and more than one-third (37 percent) had no health insurance of any kind, private or public. The 37 percent non-coverage rate for the bottom quintile of wage earners in 2008 was up from 15 percent in 1979.