Social innovation
Large cities, Fertility rates, Applied economics

Agglomeration in large metropolitan areas anda progress of fertility decline
Graduate School of Economics
Professor Kazuhiro Yamamoto
https://researchmap.jp/19750629?lang=en

Abstract
As of 2023, the lowest total fertility rate among Japanese prefectures is in Tokyo, while the highest is in Okinawa Prefecture. In
general, fertility rates tend to be lower in urban areas with high population density and higher in rural areas with low population density.
The purpose of this study is to theoretically elucidate the causes ofthis phenomenon. We will also theoretically elucidate how the declining fertility rates affects society, particularly how it affects the distribution of population between metropolitan areas and rural areas.

trends in total fertility rates in JapanThe Tokyo metropolitan area is one of the largest metropolitan areasin the world, with a population of approximately 35 million. However,while this megacity absorbs population, it does not reproduce it. Since
the fertility rate in the rural areas of Japan has been higher than that in
the urban areas for a long time, most of the population born in the rural
areas moves to Tokyo and other urban areas, producing fewer children
than the number that moved there. In other words, Japan’s urbanization
can be described as the declining fertility rates in the Tokyo metropolitan area. While there are many possible reasons for the declining fertility rates in metropolitan areas, the focus of this study is on the impactof the diversity of consumer goods in metropolitan areas. The presenceof a large population in a metropolitan area creates a huge market for
consumer goods. A huge market attracts many firms. In areas where
many firms gather, a wide variety of consumer goods are available. InTokyo and Osaka, one can find restaurants offering a variety of cuisines
not found in other parts of Japan, as well as many leisure facilities suchas yoga, fitness, dance, and other classes. This variety of consumer
goods increases the value of income in the region. The same income
can be used to obtain a variety of consumer goods, which increases
the level of satisfaction derived from the income. People living in large
metropolitan areas will try to earn more income. Specifically, they willbegin to try to work as many hours as possible. In trying to reduce theirworking hours, they sacrifice time for housework and childcare. Those

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Trends in Japan’s Total Fertility Rate
Working hours by prefecture
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Working hours（male）▍ Significance of the research and Future perspective

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Men tend to work longer hours in populous
metropolitan areas, while women work shorter
hours in metropolitan areas.
（survey on time use and leisure hours 2011)

人口200Working hours（female）

Background & Results

Almost all developed countries are experiencing declining fertility
rates, but Japan, in particular, is experiencing a declining fertility rates
at a rate unparalleled in the world. The declining fertility rates hasvarious effects on society. The lack of pension funds, a shrinking labor
force, and the shrinking market for consumer goods and the consequent withdrawal of many firms from Japan are only a few of themany problems that are expected to arise in the future. In addition, themechanism by which declining fertility rates occur is very complex.
The rising cost of education in developed countries, the increase in
the value of time lost in raising children due to rising wages, and thedecline in the relative value of marriage due to the diversification ofconsumer goods are just a few of the causes of the declining fertility
rates. This study will examine the causes and effects of the declining
fertility rates in metropolitan areas and its impact on the distribution of
population between metropolitan and rural areas.

Social innovation

Trends in Japan's Total Fertility Rate

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人口Working hours
prefecture
Total fertility rates
andbypopulationbyprefecture
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Total fertility rates by prefecture▍

who anticipate that marriage will require more time for housework will
try to delay or avoid marriage in order to have more time to work. And
those who anticipate that the birth of a child will force them to devote
much of their time to child care will try to free up time for work by having fewer children. The result of these actions is that metropolitan areas
will have fewer marriages and fewer children. Inevitably, metropolitan
areas with large numbers of businesses will have fewer marriages andfewer children.

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Population by prefecture(thousands）

Total fertility rates and population by prefecture

P a t e n tSato, Yasuhiro; Yamamoto, Kazuhiro. Population concentration, urbanization, and demographic transition. Journal of Urban Economics 2005, 58, 45-61.
doi: 10.1016/j.jue.2005.01.004
Maruyama, Akiko; Yamamoto, Kazuhiro. Variety expansion and fertility rates. Journal of Population Economics 2010, 23, 57-71.
Tr e a t i s edoi: 10.1007/s00148-008-0223-6
Morita, Tadashi; Yamamoto, Kazuhiro. Inter-regional fertility differentials and agglomeration. Japanese Economic Review 2018, 69, 171-188.
doi: 10.1111/jere.12174
URL
K e y w o r d decrease in fertility rates, agglomeration, diversity in consumer goods

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