An Empirical Evaluation of Methods to Estimate Use Tables with Imports Only Bart Los University of Groningen (WIOD Conference, Vienna, May 2010) This project is funded by the European Commission, Research Directorate General as part of the 7th Framework Programme, Theme 8: Socio-Economic Sciences and Humanities. Grant Agreement no:

Structure of national supply and use table for country

Structure of inter-country supply and use table for country A Step 1: Distinction between use of domestic inputs and imported inputs Step 2: Attribution of use of imported inputs to country of origin row

Availability of Imports Data

Domestic vs. Imported Use Only the import vector from the supply table is available: 1.Assume that ratio of imported use over total use of a product is identical across industries and final demand 2.Use information from (modified) BEC to split imports vector and assume identical ratios across industries. Different ratios for final demand. A SIOT of imports is available (for the projection year or another year): Reverse engineer a use table of imports and use product/industry-specific ratios (plus scaling) Benchmark Use table(s) of imports is/are available: 3.Use product/industry-specific ratios for benchmark (plus scaling)

SIOT-Construction: Beta version Table for 3 countries: Germany, Japan, USA (95) ( 8A) Assumption: BEC-corrected proportions Sensible results, but some implausible results for individual cells: Negative intermediate inputs Negative exports Underlying data material (use tables in basic prices) not optimal yet Approximations of split into use of domestic products and imported products imperfect

Testing of Methods Four countries for which all types of data are available (IPTS/Eurostat): Austria, Finland, Germany and Spain 1.Estimate tables of use of imports and use of domestically produced imports for 2000 (as if this information is not available), using methods 1, 2, 3a/3b. 2.Compare estimated tables to true tables (by means of weighted average percentage errors) Information about performance of methods and evidence on effects of having imperfect information.

Stability of Import Ratios (Finland) Office Machinery Services Auxiliary to Financial Intermediation Computer and Related Services

Stability of Import Ratios (Germany) Coal and Lignite

WAPE (all intermediate inputs)

Problems and Potential Solutions (I) General conclusion: use as much information as possible, gains in accuracy can be small but are rarely negative. But: Important advantage of row-uniform ratios of imports to total use: no negatives in use table for domestic use, if total use is positive BEC-corrected and Cell-specific ratios yield negatives (not too many, and generally small). Example: investment office machinery products in Finland Systematic check across countries for such products and check modify BEC if needed Changes in inventories (often negative) have an impact

Problems and Potential Solutions (II) Minimum Cross Entropy Approach Cell-specific import ratios as close as possible to benchmark year(s) Constraints 1: uses of imports do not exceed total use of the industry Constraint 2: use of imports by industries add up to imports in the supply table Try to get ideas of specific methods in construction of tables of imported use (SIOTs and Use Tables) by individual NSIs