Balassa index

What does the survey comprise?


The publication of data about the specialisation of Dutch exports in commodities in relation to the exports of the EU (without the Netherlands).

Year survey started

The current structure of the International Trade Statistics survey of the Netherlands, which is the basis for the figures, started on 1 January 1993. Figures about the specialisation of Dutch exports are available from 1996.


The frequency of publication is yearly. The frequency of collection, in the international trade statistics, is monthly.

Publication strategy

The published annual figures are definite.

How is the survey conducted?

Data sources

For Dutch trade with EU member states (Intra trade) Statistics Netherlands uses a survey with an exemption threshold. For Dutch trade with the countries that are not member states of the European Union (Extra trade) the main source is monthly customs data. The figures about the trade of the EU (without the Netherlands) are obtained from Eurostat, the statistical office of the European Union. Eurostat receives the figures of the individual member states, which each have their own method of data collection.

Survey method

Statistics Netherlands receives monthly data from enterprises and the customs authorities on imports and exports of commodities. For trade with non-EU countries, enterprises declare to the customs authorities or send the information directly to Statistics Netherlands. Statistics Netherlands receives a copy of these customs declarations or uses information from the automatic customs declaration system. Statistics Netherlands receives data about trade between the Netherlands and EU countries directly from enterprises.

Sample size

All enterprises which trade within the EU for amounts above the exemption threshold are required by law to submit data for the international trade statistics. All enterprises which trade with non-EU countries are required by law to submit data for the international trade statistics.

Checking and correction methods

Time series are used for plausibility checks. If doubts arise about plausibility, more detailed checks are carried out. Checking and correction takes place with respect to the significance of the submitted declarations.

Quality of the results


Several indicators about the level of accuracy of the results at a detailed level are available:

  • Level of non-response
  • Comparison of results with the results of partner countries (asymmetries)
  • Correction of values for insurance and transport costs (cif/fob corrections)
  • Validation by external sources.

Sequential comparability

The statistics on international trade in goods have so-called method breaks. For example, the figures about imports and exports in 2008 were calculated in a slightly different way than in previous years. The causes are a revision of the demarcation between re-exports and quasi transit trade, and the inclusion of several enterprises that were previously wrongfully not included in international trade statistics. This did not have large effects on the total imports and exports: a difference of less than 1 per cent compared to the situation before these changes. However, on a more detailed level, such as in this table, larger differences may appear.

Quality strategy

To make the figures as reliable as possible, the following measures were implemented:

  • Reminders and other measures to reduce non-response
  • Supply of user-friendly software free of charge
  • Investigation of discrepancies
  • Optimalisation of the control system