First, their data exclude workers at businesses that have more than one location; in other words, while workers at a standalone mom-and-pop restaurant show up in their results, workers at Starbucks and McDonald’s don’t. Almost 40 percent of workers in Washington state work at multi-location businesses, and since Seattle’s minimum wage increase has been larger at large businesses than at small ones — right now, a worker at a company with more than 500 employees is guaranteed $13.50 an hour, while a worker at a company with fewer than 500 employees is guaranteed only $11 an hour — these workers’ exclusion from the study’s results is an especially germane problem (note that low-wage workers in Seattle have had an incentive to switch from small firms to large firms since the minimum wage started rising). In earlier work, in fact, the University of Washington team’s results were different depending on whether these workers were included in their analysis; including them made the effects of the minimum wage look more positive. Second, the University of Washington team does not present enough data for us to assess the validity of its “synthetic control” in Washington — that is, the set of areas to which they compare the results they observe in Seattle. The Seattle labor market is not necessarily comparable to other labor markets in the state, and given some of the researchers’ implausible results, it’s hard to believe the comparison group they chose is an appropriate one.