Upon further examination, this isn't even the right question. Total employment isn't all that matters—among other things, we want to know who is holding the jobs. In a model of imperfect competition, a minimum wage has two effects. First, it decreases employment by putting a wage floor above some workers' marginal product of labor; second, it increases employment by inducing more people to enter the labor force. While the aggregate outcome may involve either higher or lower total employment, this will hide important shifts in the composition of the workforce.
What are the welfare effects of these shifts? Consider the group of people induced to enter the labor force by a small increase in the minimum wage. Since this group, by definition, consists of people who would opt to stay out of the labor force under a slightly lower wage, it gains relatively little utility from working—members of the group are still close to being indifferent toward work. Workers who lose their jobs because of the minimum wage, on the other hand, are likely to derive much higher utility from work. In particular, since they will tend to be individuals from poor backgrounds with little education, they are typically in special need of the income from a steady job.
This doesn't mean that the minimum wage is necessarily a bad idea. From a social welfare perspective, it's still possible that the direct income-increasing effects of the minimum wage will outweigh the disemployment effects. But it is critical that we know what those disemployment effects are, and looking at aggregate employment alone won't tell us.