World-systems theory was developed by sociologists such as Immanuel Wallerstein during the 1970s. In world-systems theory, semi-periphery countries are those whose state of economic development is between the most industrialized nations (known as core countries) and peripheral/periphery countries, which are less developed and have minimal impact upon the global economy. World-systems theory is an alternative to the World Bank's classification system of high-income, middle-income, and low-income countries, as well as the modern definitions of First World and Third World countries.
World-systems classes are unofficial and can vary depending upon the source. They can also change over time. Case in point: Wallerstein's 1976 list of peripheral countries differs significantly from both his 1997 list and Babones' 2005 list. Large-scale economic events such as wars, regime changes, and the COVID-19 pandemic can often influence a country's classification. For example, several new powers emerged after World War I, with the UK, Germany, and the United States becoming core countries while Spain, Portugal, and Holland became semi-periphery countries.
|Algeria||Czech Republic||Indonesia||North Korea||South Korea|
|China||Hungary||New Zealand||Saudi Arabia||Venezuela|
World-system classes are based upon economics rather than geography, although some semi-periphery countries are indeed located between core countries and peripheral nations. Mexico, for example, is typically considered to be a semi-periphery bridge between the United States (a core country and a leading global power) and various periphery countries in Central and South America.
Wallerstein (who preferred the term world-systems analysis over world-systems theory) traces the three country categories back to the end of the feudal period (1290-1450) and the rise of capitalism during the next 190 years (1450-1640). During this time, localized feudal economies gave way to greater industrialization and increased international trade. European countries adapted quickly to these trends, leveraging innovation and an advantageous geographical location to become global economic leaders. This imbalance led to unequal development, in which some countries focus upon high-value, technologically advanced finished goods and skilled services, while other countries are relegated to labor-intensive, low-skill production of raw materials and less valuable products.
Of the three country categories, core countries tend to be the wealthiest, most technologically advanced, most industrialized, and most powerful both economically and militarily. Periphery countries have the least-diverse economies, the lowest level of industrial and technological development, and a less-skilled workforce. Semi-periphery countries occupy the space between these two extremes.
According to the latest list put together by Babones, there are 14 semi-periphery countries in the world.