During the Cold War, the 'Three Worlds' model was used to classify nations. The 'First World' included capitalist Western nations, the 'Second World' referred to the Soviet Union and its communist allies, and the 'Third World' comprised non-aligned or developing nations. Ghana, as a non-aligned nation in Africa, was considered part of the 'Third World' and would not have been classified as 'Second World,' which was reserved for the Eastern Bloc.

Immanuel Wallerstein developed world-systems theory, which analyzes the global economy as a single unit. He categorized nations into core, semi-periphery, and periphery based on their economic power and exploitation dynamics, providing a framework for understanding global inequality and historical development.

Global stratification refers to the hierarchical arrangement of individuals and groups in societies around the world. It highlights the systemic patterns of social inequality that exist between nations, such as disparities in wealth, power, prestige, and access to resources. This concept helps sociologists analyze why some countries are wealthy and powerful while others remain impoverished and marginalized in the global economic system.

Newly industrializing countries (NICs) are nations whose economies have not yet reached the status of developed countries but have outpaced their developing counterparts. This transition is characterized by a significant shift from agricultural-based economies to industrial production and manufacturing, often driven by rapid economic growth and export-oriented policies.

Many nations in Asia and Africa face complex challenges including low national income, widespread absolute poverty, and significant gender disparities. These issues are interconnected, as poverty often exacerbates existing social inequalities, disproportionately impacting women and hindering overall development, which remains a critical focus of global stratification studies.

According to World Bank classifications, approximately 15% of the global population lives in high-income countries. These nations are defined by a high Gross National Income (GNI) per capita. This data point is essential for understanding global stratification and the significant economic disparities that exist between the wealthiest nations and the rest of the world.

World-systems theory suggests that peripheral nations are often caught in a cycle of dependency, relying on both core nations for capital and semi-peripheral nations for intermediate economic functions. While core nations are the primary exploiters, the structural dependency often involves the semi-periphery as a buffer zone. This classification reflects the complex global hierarchy where semi-peripheral states exert influence over the periphery while being subordinate to the core.

More developed countries (MDCs) are characterized by high levels of industrialization, advanced technology, high per capita income, and strong infrastructure. Canada, Japan, and Australia all consistently rank high on the Human Development Index (HDI), which measures life expectancy, education, and standard of living, placing them firmly in the category of highly developed nations.

Thailand, China, and Namibia are all categorized by international organizations like the World Bank as middle-income countries. This classification is based on their Gross National Income (GNI) per capita, which falls between the thresholds for low-income and high-income economies. These nations are currently experiencing varying stages of industrialization and economic development, placing them in the middle tier of the global economic hierarchy.

Gross Domestic Product (GDP) is the most widely used indicator in sociology and economics to assess the economic output and standard of living of a country. It serves as a foundational metric for analyzing global stratification, allowing researchers to categorize nations into core, semi-periphery, and periphery based on their relative economic wealth and productive capacity.