The Urban Economics Workshop 2023
空間情報科学研究センター（CSIS）との共催ワークショップ

＊今回のセミナーは日本貿易振興機構アジア経済研究所との共催です。
This seminar is co-hosted by Institute of Developing Economies, Japan External Trade Organization (JETRO).

Jacques-François Thisse (Université catholique de Louvain、ジェトロ・アジア経済研究所)
"Foundations of Cities" (with Matthew A. Turner and Philip Ushchev)

How do people choose work and residence locations when commuting is costly and productivity spillovers, increasing returns to scale, or first nature advantage, reward the concentration of employment? We describe such an equilibrium city in a simple geography populated by agents with heterogenous preferences over workplace-residence pairs. The behavior of equilibrium cities is more complex than previously understood. Increasing returns to scale and productivity spillovers can disperse employment in empirically relevant parts of the parameter space. Heterogeneous preferences concentrate employment and residence. These results have important implications for the study of agglomeration economies and the specification of quantitative spatial models.

菊池 信之介（Massachusetts Institute of Technology）
TBA

内藤 巧（早稲田大学）
TBA

内藤徹（同志社大学）
"Regional Childcare Policy, Urbanization, and Population Dynamics" (with Hiroyuki Hashimoto)

This study investigates the effects of the regional childcare policy on fertility, interregional demographics,
and capital accumulation in a two-region OLG model with endogenous fertility and publicly provided childcare
facilities. The key feature of the model is that one region has children who cannot enter the childcare facilities
(waitlisted children), whereas the other region does not have these children. The use of childcare facilities is
assumed to be assigned to parents with a positive probability that decreases with an increase in ``effective"
supply of the publicly provided childcare facilities. We demonstrate that tax increases to expand the total supply
of public childcare facilities in the region with waitlisted children may reduce the probability of becoming a
waitlisted child and increase the fertility rate in the region with waitlisted children. However, this is not applicable
in all cases. The key factor shaping variation in outcomes is the regional migration, which is induced by tax increases
that have negative effect on labor demand and positive effect on residence choice. The regional migration changes
the number of parents in the region with waitlisted children, which is an indirect effect of the taxation policy.

近藤恵介（神戸大学）
Ex ante evaluation of migration subsidy: Evidence from Japan

This study proposes a simple framework for the ex ante evaluation of migration subsidy. Recently, the Japanese government initiated a migration subsidy program to promote urban-to-rural migration for regional revitalization under the economy with a monopolar concentration in Tokyo. The ex ante evaluation framework proposed in this study formulates the payback period of interregional migration as investment behavior. In the model, households compare the sum of the expected benefits available each year after migration with the lump-sum costs of migration, which are estimated with structural estimation using the interregional migration flow data. The migration subsidy leads to an incentive for interregional migration by reducing the payback period. This study finds that households incur different migration costs at each stage of life, implying that a uniformly determined migration subsidy may have different policy effects. Counterfactual simulations provide scientific insight into the potential impact of the migration subsidy program, helping policymakers determine the optimal amount under the budget constraint.

中島賢太郎（一橋大学）
Geography of Business Interactions: Evidence from Business Card Exchange Data (with Shinnosuke Kikuchi, Shota Komatsu, Juan Nelson Martinez Dahbura, Takanori Nishida, Kensuke Teshima, and Junichi Yamasaki)

Business to business interactions in a small distance have attracted research interests as the core of agglomeration forces, but observing directly business to business interactions has been challenging. We use unique business card exchange data from Eight, a business card organizer and professional networking platform, to overcome the challenge. We find that the distance reduces business card exchanges, more so for executives. We also find that the distance elasticity of business card exchanges is highly heterogeneous across industries and that the industry-level elasticity is correlated with a standard measure of industry-level agglomeration. Overall, our results suggest that business interactions are a key determinant of agglomeration.

笹原　彰（慶應義塾大学）
"Immigration, imports, and (im)mutable Japanese labor markets." (with Yumin Sui and Emily Taguchi)

This paper investigates the effects of globalization–measured by an increase in immigration and in imports from China–on labor market outcomes in Japan. We attempt to identify the causal links using a shift-share instrument based on previous settlement patterns of migrants for immigration shocks, and the one based on previous spatial allocation of sectoral employment for import shocks. The results suggest limited impact of these variables on wages, however, significant effects are found in the late 1990s, suggesting their interactions with Japan’s Lost Decade.