For 10 points, identify this phenomenon of economic exchange.
The amount of this phenomenon in industry contexts may be measured by the Grubel–Lloyd index. Increasing returns to scale in this phenomenon produce the home-market effect. Paul Krugman critiqued a model of this phenomenon from the Stockholm school that explains it as resulting from factor endowments. This phenomenon is nonexistent in a fully autarkic economy. (*) Leontief's paradox critiques a model of it named for Heckscher and Ohlin. "Gains" from this phenomenon result from lower opportunity costs of production according to the principle of comparative advantage, which David Ricardo illustrated with Portuguese wine and English cloth. For 10 points, identify this phenomenon of economic exchange.
The amount of this phenomenon in industry contexts may be measured by the Grubel–Lloyd index.
international trade [prompt on comparative advantage or exchange until read] &lt;LS, SocSci&gt;