This article is relatively economics-heavy; so for the sake of a general audience I'll condense it a bit:

In recent research we develop a new Index of Opportunities based on a country's accumulated capabilities to undergo structural transformation. The Index captures the potential for further upgrading, growth, and development. The idea underlying the Index is that, in the long run, a country's income is determined by the variety and sophistication of the products it makes and exports, and by the accumulation of new capabilities. The Index of Opportunities has the following dimensions, all related to a country's export basket:
Overall Sophistication:

The level of sophistication of the export basket captures its income content. It is calculated as a weighted average of the income level of the products exported, where the latter is calculated as a weighted average of the GDP per capita of the countries that export a given product.
Graph 1: Showing Ranks

Overall Diversification:

The diversification of a country’s export basket is measured by the number of products in which the country has acquired revealed comparative advantage. It measures the country’s ability to compete in a wider range of products.
Graph 2: Showing Ranks

Standardness:

Another aspect of the export basket that the index captures is uniqueness, i.e., how many countries export the same product. This measure of uniqueness of the export basket has been called “standardness”. A lower value of standardness represents a more unique and therefore better export package.
Graph 3: Showing Relationship Between Diversification and Standardness

Open Forest:

This is a measure of the potential for further structural change. This variable provides a measure of the (expected) value of the goods that a country could potentially export, i.e., the products that it currently does not export with revealed comparative advantage.
Graph 4: Showing Ranks

Results:

China has the highest score, followed by India, Poland, Thailand, and Mexico. Brazil comes in 6th place and Russia in 18th.
Full Results

Source: Economists from the Asian Development Bank