A World Ranked by Countries
Zoom the stratification lens out to planetary scale: the strongest single predictor of a person's income is not talent or effort but country of birth. Global inequality is stratification between societies stacked on top of stratification within them.
The map's vocabulary has evolved: 'First/Third World' (Cold War politics) gave way to 'developed/developing', then to the World Bank's income tiers — high, upper-middle, lower-middle, low — measured by GNI per capita, usually corrected for purchasing power parity (PPP), since a euro buys different amounts of life in Oslo and Nairobi. The Human Development Index (HDI) widens the lens beyond money to health and education.
Why the gaps? Three big theory families:
- Modernization theory (Rostow): development is a staircase every country can climb — traditional society, preconditions, take-off, drive to maturity, mass consumption. Poverty = not yet climbed; remedy = technology, investment, 'modern' institutions.
- Dependency theory: the poverty of the periphery is not a starting point but a product — colonial and post-colonial trade locked poor economies into exporting cheap raw materials and importing expensive finished goods. The staircase is blocked from above.
- World-systems analysis (Wallerstein): one capitalist world economy with a core, a periphery, and a semi-periphery in between — countries can move between zones (the interesting cases: South Korea up, Argentina down), but the structure of unequal exchange persists.
The empirical shock of recent decades is convergence in parts: East Asia's growth pulled over a billion people out of extreme poverty, powered by growth-rate arithmetic — a poor economy compounding at 7% doubles each decade, while a rich one at 1-2% barely moves.
For business, the tiers are a strategy map: where the next middle class emerges, where labor costs sit, where infrastructure gaps are the product — the 'bottom of the pyramid' is both a moral fact and a market.
Three families of explanation
| Theory | Gap exists because… | Prescription |
|---|---|---|
| Modernization | Some societies haven't yet modernized | Diffuse technology, education |
| Dependency | The core develops by underdeveloping the periphery | Restructure the world economy |
| Institutionalist | Inclusive vs extractive institutions | Build inclusive rules |
Tip: Never compare living standards across countries without the PPP correction — a euro buys different amounts of life in Oslo and Nairobi, and uncorrected GNI figures overstate the gap by roughly half.