The Economic Complexity Index (ECI) and the Product Complexity Index (PCI) are, respectively, measures of the relative knowledge intensity of an economy or a product.

ECI and PCI values are estimated directly from matrices summarizing the geography of economic activity, and can be calculated on demand.

Formally, the complexity of location (ECI) is a function of the complexity of the activities present in it. Similarly, the complexity of an activity (PCI) is a function of the complexities of the locations where that activity is present.

These are the rankings of the OEC 3.0 version for the Economic Complexity Index .