Grubel–Lloyd index

The Grubel–Lloyd index measures intra-industry trade of a particular product. It was introduced by Herb Grubel and Peter Lloyd in 1971.

${\displaystyle GL_{i}={\dfrac {(X_{i}+M_{i})-\left|X_{i}-M_{i}\right|}{X_{i}+M_{i}}}=1-{\dfrac {\left|X_{i}-M_{i}\right|}{X_{i}+M_{i}}}\qquad ;\ 0\leq GL_{i}\leq 1}$

where X_i denotes the export, M_i the import of good i.

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