A study on the household's fertility choice and the determination of the aggregate fertility

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K17022
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Economic theory
• Research Institution: Kyoto University (2018); Kobe University (2015-2017)
• Principal Investigator: Yasui Daishin 京都大学, 経済学研究科, 准教授 (30584560)
• Research Collaborator: Minamimura Keiya
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 出生率 / 所得格差 / 職業の異質性 / 家計の異質性

Outline of Final Research Achievements

I developed a new theoretical framework that explains the relationship between characteristics of households and their fertility choice. In constrast to prior studies focusing on intrinsic heterogeneity between households (e.g. individual ability), I focused on heterogeneity between jobs (e.g. productivity). More concretely, my model developed in this research attributes observed wage differential between households to the result of their simultaneous choice on job and fertility, rather than intrinsic individual heterogeneity. By this perceptional change, I found that (1) my model can explain the relationship between wage and fertility that is difficult to be explained by prior theories, and (2) there can be a new channel through which aggregate shocks affect the　fertility rate, which is not identified by prior studies.

Free Research Field

Economics

Academic Significance and Societal Importance of the Research Achievements

子ども数の決定に関するほとんどすべての既存モデルにおいては、個人は自分の賃金が与えられたものとして子ども数の選択を行うという仮定が置かれている。それに対して本研究で置いた仮定は、条件が異なる複数の職が存在して、職業選択と子ども数の選択を同時にかつ合理的に行うというものである。それにより、事前に能力差がなくとも事後的に選択に違いが生じる。どちらの仮定によるかで、経済環境の変化に対して予測される家計の反応は大きく異なるので、このような新しい視点を提供したことの学術的意義は大きいと考えられる。また、少子化問題の社会的関心の高さを考えると、学術的意義だけでなく社会的意義も大きいと考えられる。