第32章世界のマクロ経済政策

The national economies that comprise the global economy are remarkably diverse. Let us use one key indicator of the standard of living, GDP per capita, to quantify this diversity. You will quickly see that quantifying this diversity is fraught with challenges and limitations. As we explained in The Macroeconomic Perspective, we must consider using purchasing power parity or “international dollars” to convert average incomes into comparable units. Purchasing power parity, as we formally defined in Exchange Rates and International Capital Flows, takes into account that prices of the same good are different across countries.

The Macroeconomic Perspective explained how to measure GDP, the challenges of using GDP to compare standards of living, and the difficulty of confusing economic size with distribution. In China’s case, for example, China ranks as the second largest global economy, second to only the United States, with Japan ranking third. However, when we take China’s GDP of $9.2 trillion and divide it by its population of 1.4 billion, then the per capita GDP is only $6,900, which is significantly lower than that of Japan, at $38,500, and that of the United States, at $52,800. Measurement issues aside, it’s worth repeating that the goal, then, is to not only increase GDP, but to strive toward increased GDP per capita to increase overall living standards for individuals. As we have learned from Economic Growth, countries can achieve this at the national level by designing policies that increase worker productivity, deepen capital, and advance technology.

The related measure gross national income (GNI) per capita also allows us to rank countries into high-, upper-middle-, lower-middle-, or low-income groups. The World Bank updates the classifications each year. Low-income countries are those with $1,085 per capita GNI per year; lower-middle-income countries have a per capita GNI between $1,086 and $4,255; upper-middle-income countries have a per capita GDP between $4,265 and $13,205; while high-income countries have over $13,206 per year per capita income. According to the 2022 classifications, there are 27 low-income nations and 80 high-income nations. The other 110 measured nations occupy the two tiers of middle-income nations, and are comprised of the vast majority—75%, of the world’s population. Despite the population and quantitative majority, these nations only produce one third of global GNI and have nearly two-thirds of the world’s people living in poverty.

An overview of the regional averages of GDP per person for developing countries, measured in comparable international dollars as well as population in 2018 (Figure 32.3), shows that the differences across these regions are stark. As Table 32.2 shows, nominal GDP per capita in 2020 for the 652 million people living in Latin America and the Caribbean region (excluding high income countries in that region) was $6,799, which far exceeds that of South Asia and sub-Saharan Africa. In turn, people in the world’s high-income nations, such as those who live in the European Union nations or North America, have a per capita GDP three to four times that of the people of Latin America. To put things in perspective, North America and the European Union (plus the United Kingdom) have slightly more than 10% of the world’s population, but they produce and consume about 44% of the world’s GDP.

Such comparisons between regions are admittedly rough. After all, per capita GDP cannot fully capture the quality of life. Many other factors have a large impact on the standard of living, like health, education, human rights, crime and personal safety, and environmental quality. These measures also reveal very wide differences in the standard of living across the regions of the world. Much of this is correlated with per capita income, but there are exceptions. For example, life expectancy at birth in many low-income regions approximates those who are more affluent. The data also illustrate that nobody can claim to have perfect standards of living. For instance, despite very high income levels, there is still undernourishment in Europe and North America.

The differences in economic statistics and other measures of well-being, substantial though they are, do not fully capture the reasons for the enormous differences between countries. Aside from the neoclassical determinants of growth, four additional determinants are significant in a wide range of statistical studies and are worth mentioning: geography, demography, industrial structure, and institutions.

Countries have geographic differences: some have extensive coastlines, some are landlocked. Some have large rivers that have been a path of commerce for centuries, or mountains that have been a barrier to trade. Some have deserts, some have rain forests. These differences create different positive and negative opportunities for commerce, health, and the environment.

Countries also have considerable differences in the age distribution of the population. Many high-income nations are approaching a situation by 2020 or so in which the elderly will form a much larger share of the population. Most low-income countries still have a higher proportion of youth and young adults, but by about 2050, the elderly populations in these low-income countries are expected to boom as well. These demographic changes will have considerable impact on the standard of living of the young and the old.

Countries have differences in industry structure. In the world’s high-income economies, only about 2% of GDP comes from agriculture; the average for the rest of the world is 12%. Countries have strong differences in degree of urbanization.

Countries also have strong differences in economic institutions: some nations have economies that are extremely market-oriented, while other nations have command economies. Some nations are open to international trade, while others use tariffs and import quotas to limit the impact of trade. Some nations are torn by long-standing armed conflicts; other nations are largely at peace. There are also differences in political, religious, and social institutions.

No nation intentionally aims for a low standard of living, high rates of unemployment and inflation, or an unsustainable trade imbalance. However, nations will differ in their priorities and in the situations in which they find themselves, and so their policy choices can reasonably vary, too. The next modules will discuss how nations around the world, from high income to low income, approach the four macroeconomic goals of economic growth, low unemployment, low inflation, and a sustainable balance of trade.