Does Rising Productivity Explain Seniority Rules for Layoffs
指出，通常认为资历规则能保留高生产率老员工的解释基于不现实的假设；当技能随经验增长时，人力资本理论反而预测应优先裁掉最资深的员工。
Seniority rules for layoffs are a widespread feature of the union and nonunion workplace. Many explanations have been offered for their existence. Some emphasize the role of unions, but others argue that seniority rules can promote economic efficiency. In this context, the rules are simple, easy to implement, and widely regarded as fair. They may help control turnover and conserve valuable investments in specific capital. They may also be a response to the higher reliability of more experienced workers. Or they may reflect the higher value young workers place on their time at home or at search.' In this company, a new explanation is hardly needed, and this note will not provide one. Rather, I will show that one of the most commonly accepted explanations is based on an assumption that is quite unrealistic. One of the most plausible explanations for seniority rules seems to follow directly from human capital theory.2 Senior workers, having had more time to invest in on-the-job training, are likely to be more productive. The seniority rule may therefore be a convenient rule of thumb which ensures that, on average, it is the less productive workers who are let go while the more productive ones are hoarded until business picks up. This argument has been given added weight by some results from implicit contract theory. When workers differ in skill levels, but share the same value of time at home, efficient contracts will always lay off the unskilled workers before the skilled ones. The natural corollary again seems to be that where senior workers are more skilled, they should be last to go.3 I show in this paper, however, that when skill grows with experience (as human capital models predict), this corollary is false. In fact, human capital growth by itself predicts that it is the most senior workers who should be laid off first. Previous writers have missed this result because they have implicitly (and unrealistically) assumed that workers continue to gain productive skills while sitting at home on layoff. My analysis will also shed light on some aspects of collective bargaining contracts and on the phenomenon of early retirement. The results are first derived in the context of an implicit contract model which is stripped of all but the barest essentials. Subsequently, the robustness of the conclusions is examined in a series of extensions. Finally, some implications of the analysis are discussed.