Appendix C.1: Data handling methodology in the UNCTAD’s Trade Analysis Information System (TRAINS)

The “Historical Non-Tariff Measures” data used for this report were downloaded from the World Bank’s World Integrated Trade Solution (WITS) database, using UNCTAD’s Trade Analysis Information System (TRAINS). The data were only downloaded in the cases where the NTM classification was based on the old trade control measures (TCM) code (before 2009), since there is no exact correspondence between old and new TCM codes.

The data were downloaded for each country-year and include information about the nomenclature, the product code at the most disaggregated level (at the most detailed commodity level of the national tariffs – for some countries up to 12-digit codes), the start year, a partial coverage indicator, and the source. The countries were chosen on the condition that they reported two or more duty codes per year. Only the countries that had available information for at least two years were retained. These data were then matched with the description and the type of measure corresponding to each NTM code.

The data were then harmonized at the HS6 digit level,1 using the following methodology. All product codes of less than six digits were expanded to include the sixdigit codes belonging to the chapter or heading. The underlying assumption is that all products within an HS6 category are horizontally affected by a non-tariff measure if it is reported at lower levels of disaggregation (the correctness of this assumption has been verified with the compilers of the original data). In the cases where NTMs were reported at a level of disaggregation higher than HS6, it was assumed that the entire HS6 line was horizontally affected. For instance, for an NTM applied to HS8 product 51051015, the HS6 line 510510 was coded as affected. This procedure can potentially inflate the shares of products and trade affected by NTMs. To

obtain a sense of whether this was a real concern, we calculated incidence ratios – the number of product lines reported to be affected by NTMs over the total number of product lines belonging to that six-digit product code (downloaded from the Tariff Download Facility of the WTO). The partial coverage indicator could not be used for calculating the NTM incidence, since there were duplicate observations. Thus, this variable was not used.2

When using incidence ratios, Di in the formulas for the share of trade and the share of lines affected is not a dummy variable, but an incidence ratio that can take values between zero and one. Results using incidence ratios are, however, not reported in this report because they are very similar to the ones obtained with Di as a dummy variable (the correlation among the indices is as high as 0.98). Results are available upon request.

The next step was to obtain the information about which products were actually imported by the reporter countries, in the years for which the NTM was reported. Import data are from UN Comtrade, at the six-digit level, with the world as trade partner. For the European Union 1999, the trade data were not available directly; thus, the gross imports of the countries that belonged to it at that time were downloaded separately and summed up. Other data were not directly available when the nomenclature did not correspond with the years. For these, the available import data were downloaded in another nomenclature, and then matched to the actual nomenclatures via correspondence tables. The countryyears handled in such a way were the Philippines (1998), Tunisia (1999) and the Bolivarian Republic of Venezuela (2003, 2004, and 2005).

Data availability

The country-year observations available are as follows: