 This work led to many unexpected insights on the effects of government policy.For example, the minimum wage might not decrease employment, as economists commonly believed, but it might induce employers to provide less on-the-job training to employees.In addition to implications for policy, Rosen's analysis of choice in characteristics space with tied sales specified the conditions under which the parameters of demand and supply function parameters for the underlying characteristics of goods could be deduced from so-called hedonic regressions.