The Grubel–Lloyd index measures

intra-industry trade Intra-industry trade refers to the exchange of similar products belonging to the same industry. The term is usually applied to international trade, where the same types of goods or services are both imported and exported. Examples Examples of this ...

of a particular product. It was introduced by Herb Grubel and Peter Lloyd in 1971.

GL_i = \dfrac = 1 - \dfrac \qquad ;\ 0 \leq GL_i \leq 1

where ''X_i'' denotes the

export An export in international trade is a good produced in one country that is sold into another country or a service provided in one country for a national or resident of another country. The seller of such goods or the service provider is a ...

, ''M_i'' the

import An importer is the receiving country in an export from the sending country. Importation and exportation are the defining financial transactions of international trade. Import is part of the International Trade which involves buying and receivin ...

of good ''i''. If ''GL_i'' = 1, there is a good level of intra-industry trade. This means for example the Country in consideration Exports the same quantity of good ''i'' as much as it Imports. Conversely, if ''GL_i'' = 0, there is no intra-industry trade at all. This would mean that the Country in consideration only either Exports or only Imports good ''i''.

References

* * International trade theory {{international-trade-stub