Divided nations as natural experiments
Editorial · East vs West Germany / North vs South Korea / what the comparison controls for
Germany and Korea split populations sharing language, culture and history, then ran opposite systems on each half. This is the closest thing social science has to a controlled experiment on economic systems.
The claim
Social science almost never gets a controlled experiment. Germany and Korea came close: each split a single population — one language, culture and history — and ran opposite economic systems on the two halves, holding culture and geography roughly constant in a way ordinary cross-country comparisons cannot.
- Korea, divided from 1948. A common history cut at the 38th parallel. By any serious estimate the South is now many times richer per head than the North — the North's own data are unreliable, but even cautious comparisons put the gap at roughly an order of magnitude (Acemoglu & Robinson, Why Nations Fail, 2012).
- Germany, 1949–90. East Germany was among the most advanced planned economies in the world and still fell substantially behind West Germany in output, consumer goods and living standards — a gap plainly visible at reunification and expensive to close.
- Exit ran one way. Migration flowed overwhelmingly from the communist side, and both states ultimately had to physically prevent their own people from leaving — the Berlin Wall and the DMZ are the starkest verdicts their own citizens delivered.
- The gap was qualitative, not just headline output. It showed in product quality, innovation, environmental degradation and everyday consumer choice — not only in GDP figures, whose comparability across systems is itself contested.
- Why the design matters. Because culture, language and initial conditions are held roughly fixed, the divergence is hard to pin on anything but the institutions — the cleanest available evidence that the system, not the people, drove the outcome.
The scholarly debate
How much of the gap belongs to the system versus confounds: war damage, Soviet reparations and extraction from the East, Marshall Plan aid to the West, Northern isolation and autarky, and differing initial industrial bases. The honest reading is that the experiment is powerful but not clean — institutions explain most, though not all, and the figures (especially North Korea's) carry wide error bars.
Strongest counterargument
◆ Against this entry’s own thesis
Critics rightly note the halves did not differ only in their economic system. East Germany was stripped of capital as Soviet reparations while West Germany received Marshall aid; North Korea was flattened by bombing in 1950–53 and later isolated by sanctions and its own autarky. So "the system" was never the *only* variable, and a fair verdict has to discount for those confounds. The rejoinder: the confounds cut in both directions and shrink over decades, yet the gap kept *widening* — which is hard to explain if institutions were not doing most of the work.