.labor, to shore up union power, or to restrict the entry of low-skilled workers into the . As the growth in the college premium slowed in the mid-1990s, education- and training-related policies received less attention, but in light of more recent upturns, they may regain popularity. Studies testing the SBTC theory have produced mixed results. The early case in support of the hypothesis was based primarily on the observation of concurrent trends at the macro leve