Core nations control global markets and use the resources and labor of periphery and semiperiphery nations.
One approach for comparing countries is based on the concept of developed, developing, and undeveloped nations. Social demographers use these terms. However, sociologists do not use these terms because the label "developing nation" can carry a negative connotation, implying that these nations are viewed as inferior or primitive. In sociology, nations are categorized as high-income, middle-income, and low-income, or as core, semiperiphery, and periphery. Institutions such as the World Bank and the United Nations (UN) use various measures, such as gross national income (GNI), to classify countries. Sociologists consult data collected by major international organizations, such as the World Bank and the UN, to classify and analyze countries.
The idea of core, periphery, and semiperiphery nations is a central concept of world-systems theory, the idea that a world economic system exists in which wealthy nations exploit poor ones to help generate their wealth. American sociologist Immanuel Wallerstein (b. 1930) first developed world-systems theory in the 1970s. World-systems theory is a total system theory, a theory that seeks to explain a complex whole and how its components are related. World-systems theory provides a framework for understanding how the productivity of all nations is interconnected by an economic network that is global.
A core nation is a wealthy, industrialized nation that controls and benefits from the global economy. Core nations have complex infrastructures, strong governments, cosmopolitan cities, and diverse economies. They control the global market and use it to their advantage by exploiting periphery nations for their cheap labor and natural resources. They also have strong militaries and international partnerships. Core countries include the United States, Canada, the United Kingdom, much of Western and Northern Europe, Australia, and Japan.
A periphery nation is a low-income nation that depends on and is exploited by wealthier nations. Periphery nations have little global power. They have weak, decentralized governments, poor infrastructure, and low education levels. Periphery nations often depend on a single industry or export to support their economies and have large rural populations. Periphery nations include much of sub-Saharan Africa, Southeast Asia, and some nations in Central and South America.
A semiperiphery nation exhibits characteristics of both core and periphery nations. These nations are generally industrializing and could be elevated to core nation status with development. Semiperiphery nations include China, India, Mexico, Brazil, South Africa, and Israel.