The Rybczynski theorem was developed in 1955 by the Polish-born English economist

Tadeusz Rybczynski Tadeusz Mieczysław Rybczyński (also Rybczynski; 1923–1998) was a Polish-English economist who is known for the development of the Rybczynski theorem (1955). He studied at the London School of Economics , mottoeng = To under ...

(1923–1998). It states that at constant relative goods prices, a rise in the endowment of one factor will lead to a more than proportional expansion of the output in the sector which uses that factor intensively, and an absolute decline of the output of the other good. In the context of the

Heckscher–Ohlin model The Heckscher–Ohlin model (, H–O model) is a general equilibrium mathematical model of international trade, developed by Eli Heckscher and Bertil Ohlin at the Stockholm School of Economics. It builds on David Ricardo's theory of comparat ...

of international trade, open trade between two regions often leads to changes in relative factor supplies between the regions. This can lead to an adjustment in the quantities and types of outputs between the two regions. The Rybczynski theorem explains the outcome from an increase in one of these factor's supply as well as the effect on the output of a good which depends on an opposing factor. Eventually, across both countries, market forces would return the system toward equality of production in regard to input prices such as wages (the state of

factor price equalization Factor price equalization is an economic theory, by Paul A. Samuelson (1948), which states that the prices of identical factors of production, such as the wage rate or the rent of capital, will be equalized across countries as a result of interna ...

Relationship between endowments and outputs

The Rybczynski theorem displays how changes in an

endowment Endowment most often refers to: *A term for human penis size It may also refer to: Finance *Financial endowment, pertaining to funds or property donated to institutions or individuals (e.g., college endowment) *Endowment mortgage, a mortgage to b ...

affects the outputs of the goods when full

employment Employment is a relationship between two parties regulating the provision of paid labour services. Usually based on a contract, one party, the employer, which might be a corporation, a not-for-profit organization, a co-operative, or any othe ...

is sustained. The theorem is useful in analyzing the effects of

capital Capital may refer to: Common uses * Capital city, a municipality of primary status ** List of national capital cities * Capital letter, an upper-case letter Economics and social sciences * Capital (economics), the durable produced goods used f ...

investment, immigration and emigration within the context of a Heckscher-Ohlin model. Consider the diagram below, depicting a labour constraint in red and a capital constraint in blue. Suppose production occurs initially on the production possibility frontier (PPF) at point A. Economics rybczynski theorem diagram

Suppose there is an increase in the labour endowment. This will cause an outward shift in the labour constraint. The PPF and thus production will shift to point B. Production of clothing, the labour-intensive good, will rise from ''C''₁ to ''C''₂. Production of cars, the capital-intensive good, will fall from ''S''₁ to ''S''₂. If the endowment of capital rose the capital constraint would shift out causing an increase in car production and a decrease in clothing production. Since the labour constraint is steeper than the capital constraint, cars are capital-intensive and clothing is labor-intensive. In general, an increase in a country's endowment of a factor will cause an increase in output of the good which uses that factor intensively, and a decrease in the output of the other good.

Relationship between endowments and outputs

See also

Further reading