Incentives, Productivity, and Labor Contracts
通过对比工薪劳动者与自雇者的年龄-收入曲线，检验了收入曲线陡峭程度与工作激励的关系，发现激励需求而非在职培训是曲线斜率的主要解释因素。
The relationship between age-earnings profiles and worker incentives is examined by contrasting wage and salary workers with the self-employed. It is argued that the steepness of wage and salary workers' age-earnings profiles reflects the desire to provide work incentives to those workers. Since self-employed workers do not face this agency problem, they are used as a benchmark to gauge productivity. Empirical support of the proposition is provided, and the effects of human capital accumulation are separated empirically from incentive effects. The most important conclusion is that under some strong assumptions, most of the slope in age-earnings profiles is accounted for by the desire to provide incentives, rather than by on-the-job training.