Wage and Productivity Differentials in Japan: The Role of Labor Market Mechanisms

Two stylized facts characterized Japan during the so-called Lost Decade (1992-2005): rising wage inequalities and increasing productivity differentials at the firm level. Surprisingly, these features have never been connected in the literature. This paper attempts to fill this gap by proposing an explanation focusing on labor market mechanisms. We first construct an efficiency wage model with two types of firms distinguished by their job security schemes and associated incentive mechanisms. We show that a comparable negative productivity shock at the aggregate level leads to different firm reactions; namely, the model predicts increasing effort from workers in firms employing an efficiency wage mechanism. This leads to increasing productivity and wage differentials and a rise of the share of these firms in the total population of firms. We test this model using Japanese micro data. For the first time, we match the Basic Survey on Wage Structure and the Employment Trend Survey for 2005. The matched worker-firm dataset we obtain allows us to confirm the existence of an efficiency wage mechanism on average. We also divide our sample of firms into two groups using the unknown regime switching regression a la Dickens and Lang (1985), and find that the primary sector, unlike the secondary, is characterized by efficiency wages. We confirm this result with various robustness checks. Finally, we simulate the evolution of the share of the primary sector in the economy and find that it substantially increased between 1981 and 2005 in line with the predictions of our model.