In a 2009 paper (behind a paywall) in the peer-reviewed, British Journal of Industrial Relations, Hristos Doucouliagos and T.D. Stanley report the results of their meta-study of 64 studies of the effects of the minimum wage on teenage employment in the United States. The chart below, taken from their paper, presents their key finding. The estimated employment effects, which are displayed along the x-axis, include both negative and positive values. Following standard statistical procedures, however, the researchers have also weighted each estimate by its statistical precision, which is measured on the y-axis. The higher up an estimate lies, the more precise it is.
What is most striking about the chart is that all of the most precise estimates are at or very close to zero — the point where the minimum wage has no effect on teen employment.