Wal-Mart's news, though met with enthusiasm by many, was also doused in heavy criticism by groups such as OUR Walmart. That organization, which campaigns for higher wages at the retailer, said that while it was pleased with to see a pay bump for the Wal-Mart employees, it still isn't enough.
"Especially without a guarantee of getting regular hours, this announcement still falls short of what American workers need to support our families," the organization said in a statement.
That argument is one of the key points raised by Wal-Mart's detractors, who say that pay raises are not sufficient when employees aren't scheduled for enough hours.
A recent study by the Retail Action Project, a group that advocates for workers, found that out of 236 retail employees surveyed, only 40 percent had set minimum hours each week. One-quarter of the respondents said they are scheduled for on-call shifts, and sometimes find out if they're needed only two hours in advance.
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Though it saves money for employers, this practice prevents part-time workers from potentially picking up extra hours at another job. It also makes it challenging for employees to be assured they will receive a steady income.
"Part-time workers need their employers to schedule them for enough hours so that they can earn enough to support themselves," said Janna Pea, spokesperson for the Retail Action Project.
"The bottom line is that even with this long overdue [pay] increase, the women and men who have made Wal-Mart so successful over the years are still struggling to support themselves and their families."
According to Lundberg, fewer than half of Wal-Mart workers are part-time, and none of its workers are on-call. As the largest private employer in the U.S., 1.2 million people work for its Wal-Mart U.S. unit.