経済発展と労働の部門間移動 〜その役割と問題〜

●Michael Spence, “Engines of Growth”（Hoover Digest 2007 No. 3）

なぜ中国やインドといった国々の急成長が実現したのか、これらの国々の急成長を可能にした成長のエンジンは一体何なのか、これらの国々の経済発展を支える共通の要因は何なのか、に関するスペンスの分析。スペンスがこれらの質問にいかなる回答を寄せているかに興味がある方は直接ご自身で上記リンク先の文章にあたっていただくとしまして（要約するには内容が濃すぎるもので、なんて言い訳してみたり）、以下私が特に興味をひかれた部分を引用。

In the early stages of rapid growth, the agricultural sector is usually the location of a vast majority of the people. Typically, labor is underemployed in such traditional sectors, and thus people move to cities and new industrial sectors where investment is taking place and productivity is higher. The loss in output in the traditional sector is minimal or zero because of the surplus labor condition, and hence the overall productivity gain is substantial. See figure 2 for the percentage of the population that is rural in India and China. This movement of people geographically and across sectors is not an ancillary side effect of the growth process but rather the essence of it.

The difference between the growth rate of GDP per capita and GDP per worker in China (figure 1) is very close to the 1 percent per annum decline in the rural population: the movement of people to high-growth and high-productivity sectors that serve the demands of the global economy. It is worth noting that this movement of people is a major challenge in the development process. In the case of China, 1 percent represents 13 million people moving to cities each year, with attendant needs for infrastructure, education, and services.

As people move and productivity rises, it is possible for everyone to be better off. But those who move to new sectors first have higher productivity and higher incomes, resulting in a pronounced tendency for income inequality to rise for an extended period. While this is a natural consequence of the process, it presents a challenge. Excessive inequality of income and wealth is not only a normative problem in most societies; it is also socially and politically disruptive and can threaten the support for the policies and public-sector investments that in part sustain the growth process. As a result, such inequalities need to be mitigated through the redistribution of income or other important services such as health care, education, and pensions, and by ensuring that access to infrastructure (clean water, transportation, power) is reasonably equitable.

Institutions and policies that retard the movement of people and resources will also retard growth, which is true in advanced as well as developing economies. Such policies may nevertheless be justified on the ground of protecting people from the full effect of market forces. But such protections are best if they are transitory, not permanent; generally it is better to protect people and incomes rather than jobs and firms. The latter approach impedes the competitive responses of firms in the private sector and, in the context of the global economy, becomes very expensive.

経済発展の過程における労働者の都市への移動は成長の結果というよりもそれ自体成長の原因（成長のエンジンの一つ）を構成していると考えるべきである。余剰労働力を抱えた農業（伝統）部門から新たな産業部門へと労働者が移動することによって経済全体の生産性が上昇し（労働者が新たな産業部門へ移動することによって両部門間でのネットの生産性の違いの分だけ経済全体の生産性は上昇する）、そのことが経済成長の促進につながっていると考えられるからである。しかしながら、労働者が農村から都市へと移動する過程（あるいは労働者の部門間移動の過程）にはこのようなプラスの面ばかりではなく、労働者の受け入れ先におけるインフラ・各種公共サービスの整備の必要性と並んで労働者の部門間移動の進展につれて露わになる所得格差に伴う問題もまた存在している。所得格差の問題への対処は、公共投資あるいは政府支出の使途への影響や労働の部門間移動への介入（例．倒産しそうな企業への政府支援、労働者の職の補償）等を通じて経済成長を阻害する結果ともなりうる。