<論文>労働組合と非正規労働者 --パートの比率に着目する--

Abstract

Japan has witnessed a significant increase in contingent employment since the 1990s. A majority of establishments in Japan use regular workers and contingent workers simultaneously. In this paper, the author focuses on unions to determine how they have balanced diversity in the workplace, and how they have influenced the percentage of part-time workers on the establishment level. The author divides the effects of unions at both the industrial and establishment level. Furthermore, the author divides establishment-level unions into three types based on the participants. Specifically, the first one is the establishment union that limited its participants to regular workers, the second one is the establishment union also included contingent workers besides the regular workers, and the third one is the establishment that has no union. This paper addresses these issues by analyzing the "Survey on Diversified Types of Employment" conducted by the Japan Institute for Labor Policy and Training (JILPT) in 2010. In the analysis, this paper will apply a tobit regression model, and differentiate between the small or medium-sized establishments and large establishments. The statistical results show that unions have generally reduced the percentage of part-time workers at the establishment level. Specifically, 1) the percentage of part-time workers at the establishment level tend to be low in when the unionization rate at the industrial level is high, 2) the percentage of part-time workers at the establishment level tend to be lower when establishment-level unions limited its participants to regular workers than other types of union, and 3) when there is a high industrial unionization rate, the difference between different types of unions at the establishment level will be smaller. However, these three observations apply only to large establishments. For small or medium-sized establishments, whether the establishment is in service industry influenced the percentage of part-time workers at the establishment level.