Economic theory once made a confident prediction about minimum wages: raise the price of labour and employers will buy less of it. Empirical work has proved considerably more equivocal. Studies comparing neighbouring jurisdictions when one raises its floor tend to find employment effects that are small and, in a substantial number of cases, statistically indistinguishable from zero. This does not show that the prediction is wrong in principle, and few economists claim that it does; what it suggests is that labour markets deviate from the competitive model enough for modest increases to be absorbed through prices, turnover and profit margins. The disagreement in the field is now largely about where the threshold lies rather than about whether one exists.