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comparison 223 common industries. 4 These industries were regrouped into 19 different branches
according to the US Standard Industrial Classification 1987. We excluded branch 29 "Petroleum
refining and related industries", as it is strongly linked to the natural resource endowments of the
countries.
The second step consisted of matching products within each of the common industries in the
bilateral comparisons. An example is provided in Table 1 for branch 27 "Printing and Publishing" in
the Mexico/USA comparison. Within this branch, 4 common industries are defined. Within two
groups of industries (US 1987 SIC codes 27.41/51/52/53/54/59/61/71/82/89 and 27.91/93/95/96), it
was impossible to match any items. In industry group 2711/21, we were able to match one product,
and in industry 2731/32, six products were matched.
The UVRs of the product matches were aggregated in three steps, of which the first two are
illustrated in Tables 1 and 2 respectively. From the product to the industry level, the product UVRs
were weighted by either the US or the Mexican quantities. The second aggregation step from the
industry to the branch level is shown in Table 2, which recapitulates the UVRs of the industries of
Table 1. As in the industry groups 27.41/51/52/53/54/59/61/71/82/89 and 27.91/93/95/96 no
matchings could be made, their weight equals zero. For the common industry 27.11/21 with only one
match, no coefficient of variation could be derived. The weight of this industry equals the value of the
one matched product. In common industry 2731/32, several product were matched. As the coefficient
of variation of the UVRs is below 0.1, they are considered representative for the total industry.
Therefore the weight of this industry equals total output instead of the value of matched products (in
grey). If the coefficient would have been above 0.1, then only its matched output would have been
included in the weighting scheme. The "final" weights are converted to a common currency using the
industry UVRs of Table 1. Finally, the branch UVRs are obtained as shown in columns (11) to (13).
4 The correspondances of the industry nomenclatures are available upon request from the authors.
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