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===Source data===

===Source data===

The Product Space uses international trade data from Feenstra, Lipset, Deng, Ma, and Mo's ''World Trade Flows: 1962-2000'' dataset,<ref>R.R. Feenstra, H.D. Lipsey, A. Ma, H. Mo, ''HBER Work. Pap 11040'' (2005).</ref> cleaned and made compatible through a [[National Bureau of Economic Research]] (NBER) project. The dataset contains exports and imports both by country of origin and by destination. Products are disaggregated according to the Standardized International Trade Code at the four-digit level (SITC-4). Focusing on data from 1998-2000 yields 775 product classes and provides for each country the value exported to all other countries for each class. From this, a 775-by-775 matrix of proximities between every pair of products is created.[[File:ProductSpaceMatrices.png|thumb|right|upright=2|'''A.''' The Product Space matrix sorted by SITC4 classification. '''B.''' The Product Space hierarchically sorted reveals modularity and that 775 products are actively traded.]]

The Product Space uses international trade data from Feenstra, Lipset, Deng, Ma, and Mo's ''World Trade Flows: 1962-2000'' dataset,<ref>R.R. Feenstra, H.D. Lipsey, A. Ma, H. Mo, ''HBER Work. Pap 11040'' (2005).</ref> cleaned and made compatible through a [[National Bureau of Economic Research]] (NBER) project. The dataset contains exports and imports both by country of origin and by destination. Products are disaggregated according to the Standardized International Trade Code at the four-digit level (SITC-4). Focusing on data from 1998-2000 yields 775 product classes and provides for each country the value exported to all other countries for each class. From this, a 775-by-775 matrix of proximities between every pair of products is created.[[File:ProductSpaceMatrices.png|thumb|right|upright=2|'''A.''' The Product Space matrix sorted by SITC4 classification. '''B.''' The Product Space hierarchically sorted reveals modularity and that 775 products are actively traded.]]