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Methodology

This section provides links to downloadable documents for understanding how WITS calculates statistics. Documents are also available as compressed files (zip format).

• UNCTAD Coding System of Trade Control Measures (Codes valid for data from 1988 to 2008)
  Download Word document (35Kb) - Download Zip file (32 Kb) -
  
• Multi-Agency Classification of Non-Tariff Measures
  Download pdf document (57Kb) - Download Zip file (55 Kb) -
  
• UNCTAD, Division on International Trade in Goods and Services, and Commodities, "Calculation Of Ad Valorem Equivalents Of Non-Ad Valorem Tariffs - Methodology Notes", DRAFT – October 2001.
  - Download Word document (158Kb) - Download Zip file (24 Kb) -
  
• WTO, Negotiating Group on Market Access, "Incidence Of Non-Ad Valorem Tariffs In Members' Tariff Schedules And Possible Approaches To The Estimation Of Ad Valorem Equivalents", TN/MA/S/10, 20 May 2003
  - Download Word document (252Kb) - Download Zip file (50 Kb) -
  
• Martin W.,"Optimal indexes of Protection", note, October 2003.
  - Download Word document (26Kb) - Download Zip file (6 Kb) -
  
• Brenton P.,"Export Diversification Issues and Indicators", note, October 2009.
  - Download pdf document (39Kb) - Download Zip file (37 Kb) -
  
• Cadot O.,"A Guide To Trade Data Analysis, note, September 2010.
  - Download pdf document (955Kb) - Download Zip file (932 Kb) -
  
• Sam Laird & Alexander Yeats, "THE UNCTAD TRADE POLICY SIMULATION MODEL - A note on the methodology, data and uses", October 1986.
  - Download pdf document (170Kb) - Download Zip file (151 Kb) -
  
• Joseph Francois & H. Keith Hall, "Global Simulation Analysis of Industry-Level Trade Policy", October 2002.
  - Download pdf document (242Kb) - Download Zip file (227 Kb) -