What is the Rybczynski theorem in simple terms?

If prices stay the same and one factor of production grows, the industry that uses it heavily expands by even more, while the other industry actually shrinks.

How is it related to the Stolper–Samuelson theorem?

Stolper–Samuelson links goods prices to factor prices, while Rybczynski links factor endowments to outputs; Jones (1965) showed the two are mathematical duals.

Rybczynski Theorem

📈 Economics By CampusDown Wiki Editorial Team Last updated October 26, 2026

The Rybczynski theorem is a theorem of international trade theory stating that in an economy with two goods and two factors, if relative goods prices stay constant, an increase in the endowment of one factor, such as capital, raises output of the good that uses that factor intensively by proportionally more than the factor increase, and reduces output of the other good absolutely. Tadeusz Rybczynski proposed it in 1955.

Contents

1. Its place in the Heckscher–Ohlin framework
2. The theorem and the magnification effect
3. Applications and evidence
4. FAQ
5. References

Its place in the Heckscher–Ohlin framework

The Heckscher–Ohlin theory of Heckscher (1919) and Ohlin (1933) holds that countries export goods that use their abundant factors intensively. Its two-good, two-factor model yields four core theorems: the Heckscher–Ohlin theorem, factor price equalization, the Stolper–Samuelson theorem (1941) and the Rybczynski theorem (1955). Whereas Stolper–Samuelson concerns how changes in goods prices affect factor prices, Rybczynski concerns how changes in factor endowments affect outputs.

The theorem and the magnification effect

Consider an economy in which textiles are labor-intensive and machinery is capital-intensive. If goods prices are given by world markets and stay fixed, factor prices and each industry's factor proportions also stay fixed. If capital then rises by 10 percent, employing all the new capital requires the machinery industry to expand, and because machinery also needs some labor, it must draw labor away from textiles. As a result, machinery output rises by more than 10 percent and textile output falls absolutely. Ronald Jones (1965) formalized this as the magnification effect and showed that the Rybczynski and Stolper–Samuelson theorems are mathematical duals.

Applications and evidence

The theorem became a tool for analyzing many real-world phenomena. In Corden and Neary's (1982) model of Dutch disease, the resource movement effect, in which a natural resource boom pulls factors into the resource sector and shrinks manufacturing, follows Rybczynski logic. Leamer (1984) and Harrigan (1995, 1997) tested with OECD data whether factor endowments explain the industrial structure of output, finding broad support once technology differences are taken into account. Immigration research has asked whether increases in labor supply by skill are absorbed by changes in industry mix rather than wages: Hanson and Slaughter (2002) and Gandal, Hanson and Slaughter (2004) reported that industry mix and technological change absorbed labor supply shocks in U.S. state and Israeli data, while Lewis (2011) emphasized adjustments in technology choice. Feenstra (2016) presents the theorem as standard material in modern trade theory.

FAQ

What is the Rybczynski theorem in simple terms?: If prices stay the same and one factor of production grows, the industry that uses it heavily expands by even more, while the other industry actually shrinks.
How is it related to the Stolper–Samuelson theorem?: Stolper–Samuelson links goods prices to factor prices, while Rybczynski links factor endowments to outputs; Jones (1965) showed the two are mathematical duals.

Sources reviewed: 2026-10-26

References

Rybczynski, T. M. (1955). Factor endowment and relative commodity prices. Economica, 22(88), 336–341.
Heckscher, E. F. (1919). The effect of foreign trade on the distribution of income. Ekonomisk Tidskrift, 21, 497–512.
Ohlin, B. (1933). Interregional and International Trade. Cambridge, MA: Harvard University Press.
Stolper, W. F., & Samuelson, P. A. (1941). Protection and real wages. Review of Economic Studies, 9(1), 58–73.
Jones, R. W. (1965). The structure of simple general equilibrium models. Journal of Political Economy, 73(6), 557–572.
Corden, W. M., & Neary, J. P. (1982). Booming sector and de-industrialisation in a small open economy. Economic Journal, 92(368), 825–848.
Leamer, E. E. (1984). Sources of International Comparative Advantage: Theory and Evidence. Cambridge, MA: MIT Press.
Harrigan, J. (1995). Factor endowments and the international location of production: Econometric evidence for the OECD, 1970–1985. Journal of International Economics, 39(1–2), 123–141.
Harrigan, J. (1997). Technology, factor supplies, and international specialization: Estimating the neoclassical model. American Economic Review, 87(4), 475–494.
Hanson, G. H., & Slaughter, M. J. (2002). Labor-market adjustment in open economies: Evidence from US states. Journal of International Economics, 57(1), 3–29.
Lewis, E. (2011). Immigration, skill mix, and capital skill complementarity. Quarterly Journal of Economics, 126(2), 1029–1069.
Feenstra, R. C. (2016). Advanced International Trade: Theory and Evidence (2nd ed.). Princeton: Princeton University Press.
Gandal, N., Hanson, G. H., & Slaughter, M. J. (2004). Technology, trade, and adjustment to immigration in Israel. European Economic Review, 48(2), 403–428.

Reports and materials that use this theory (Korean)

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This article was last updated on October 26, 2026. It is based on widely recognized original works and textbooks; when citing it in a paper, please check the original sources listed in the references.