What is covered by the survey?
The international trade and transit trade statistics give insight into the international commodity flows from, to and through the Netherlands.
The statistics of import, export and transit trade measure the international, physical goods flows that are unloaded, loaded, delivered or dispatched on Dutch territory in Europe.
The statistics consist of the StatLine table International trade and transit trade; value, weight, goods, transport mode.
The table describes the value and gross weight of international goods flows broken down by commodity group, transport mode, cargo type (containerized or non-containerized goods), country group of origin or destination and country group of loading or unloading. The following commodity flows are distinguished: total inbound transport, total imports, imports for domestic use, imports for re-exports, total inbound transit trade, inbound quasi-transit trade, inbound transport transit trade, balance customs warehouse storage, total outbound transport, total exports, exports of Dutch products, re-exports, total outbound transit trade, outbound quasi-transit trade, outbound transport transit trade and customs warehouse transit trade.
The definitions of these commodity flows can be found in the table explanation of the above-mentioned StatLine table.
Start of the survey
These statistics cover the period from 2007 onwards.
Generally, new, provisional figures become available approximately one year after the end of the reporting year. Figures on international commodity flows are subject to adjustment when new or updated source data become available. As a result, the status of the figures will be provisional for a longer period of time.
How is the survey conducted?
The international trade and transit trade statistics integrate statistics of international trade in goods and statistics on maritime transport, inland shipping, rail transport, road transport, air transport and pipeline transport. Dutch road transport data have been supplemented with data on road transport from other EU member states to and from the Netherlands. The values of imports, exports, re-exports, quasi-transit trade and customs warehouse flows are based on international trade statistics. The gross weights of these flows are also based on international trade statistics. Transport statistics constitute the basis for data on gross weight by transport mode.
Global structure integration framework
The statistics of import, export and transit trade are based on integration of the international trade in goods statistics and the transport statistics for six modes of transport. On micro-level (trade transactions), trade volumes were converted into gross weights and the transport mode of trade has been checked and corrected. To ensure comparability with the trade figures, the transport weights in non-specific commodity groups (especially general cargo) have been assigned to specific commodity groups. Furthermore, a correction has been made to the maritime and road transport figures to prevent double counting of the roll-on-roll-off transport. Using value-to-weight ratios per year, flow direction, commodity group and transport mode, the value of the goods transported was estimated. After aggregation to the 20 commodity groups, six transport modes, two cargo types (containerized or non-containerized goods) and 36 country groups, a Bayesian integration model was used to improve data consistency.
The Bayesian integration model ensures that data by commodity group, transport mode, cargo type and country group meet the following logical restrictions:
→ Inbound transport = Imports for domestic use + Imports for re-exports + Inbound quasi-transit trade + Inbound transport transit trade + Balance customs warehouse storage (applies to value and gross weight)
→ Outbound transport = Exports of Dutch products + Re-exports + Outbound quasi-transit trade + Outbound transport transit trade + Customs warehouse transit trade (value and gross weight)
→ All commodity flows ≥ 0 (value and gross weight)
Furthermore, for all commodity groups the following must apply:
→ Imports for re-exports ≤ Re-exports (value)
→ (1 – βW) * Imports for re-exports ≤ Re-exports ≤ (1 + βW) * Imports for re-exports (gross weight)
→ (1 – βQ) * Inbound quasi-transit trade ≤ Outbound quasi-transit trade ≤ (1 + βQ) * Inbound quasi-transit trade (gross weight)
→ (1 – βR) * Inbound transport transit trade ≤ Outbound transport transit trade ≤ (1 + βR) * Inbound transport transit trade (value and gross weight)
→ | Balance customs warehouse storage – Customs warehouse transit trade | < βO * Customs warehouse storage capacity
The βW factor is initially set at 0.04. The factor is incrementally increased if it appears that it is not possible to have the data comply with all restrictions. First, βW is increased to 0.08, then to 0.12 and finally to 0.18. The factors βQ and βR are initially set at 0.02. These factors are also increased step by step if not all restrictions can be met. First, they are increased to 0.04, then to 0.08 and finally to 0.12. The fraction βO equals 0.2 for gross weight and 0.4 for value.
The equations exclude the inbound and outbound transport of goods that are not destined for the market. Among others, this concerns used packaging, removal goods, luggage accompanied by travellers, used equipment from construction companies and fairs and vehicles transported for repair purposes. The weight of these specific goods is added to the transport after applying the model. The (trade) value of these goods is assumed to be nil.
The international trade statistics register the shipment of goods from the country of origin to the Netherlands and the shipment of Dutch products to the country of destination. The transport statistics record the last country where the goods were loaded on the transport means that took the goods into the Netherlands. Furthermore, the transport statistics record the first country where the goods are unloaded from the transport means that brought the goods outside the Netherlands. Therefore, a link has been made between the country groups of origin in trade statistics and the country groups of loading in transport statistics. This has been done by determining for each country group the chances of the goods being transhipped in the other country groups for transport to the Netherlands. This was carried out for each combination of commodity group, mode of transport and cargo type. For this computation, insights from the theory of gravitation models were used. The same method was applied for the outgoing flows. The results were then used to convert the transport data per country group of loading or unloading into data per country group of origin or destination.
Due to the integration method and definition differences, the figures in the StatLine table on international trade and transit trade can vary from figures in other tables on international trade and transport. After the integration of international trade and transport statistics, estimated imports and exports data differ from the original imports and exports data according to the international trade statistics. These differences are modest, usually less than 4 percent. The differences arise because trade figures are slightly adjusted to make sure that the above-mentioned restrictions are met. Adjustment always takes place within the pre-estimated reliability margins around the original figures. The estimated transport totals after integration and the totals in the original transport statistics usually differ by less than 10 percent. These differences are due to the fact that the integration of trade and transport statistics leads to a more complete description of transport and to adjustment within the estimated margins. Furthermore, the figures on total transport published in other tables are expressed in terms of gross-gross weights (i.e. including container weight) instead of gross weights.
What is the quality of the results?
From 2008 onwards, data on imports and exports are calculated in a slightly different manner compared to the preceding years as a result of the revised definition of re-exports and quasi-transit trade and the inclusion of several companies which, in the past had incorrectly not been included in international trade statistics. The total volume of imports remains virtually unchanged. The value of exports in 2008 is estimated to be 3 billion euros (less than 1 percent of the total) lower than if these changes would not have been implemented. This difference remains within the reliability margins for integrated trade and transport figures. At a more detailed level, relatively larger differences may occur. This change has no consequences for total transport and the estimated transit trade. More information about this break in the series and its effect on international trade statistics can be found in the additional survey description Internationale goederenhandel, trendbreuk 2007-2008 (only available in Dutch).
International data on imports and exports for 2013 are not entirely comparable with those for 2012, as the revised figures for 2013 are based on an improved estimation method for ‘refuelling (bunkering) in international shipping and aviation'. The implementation of the new method caused exports to rise by nearly 5 billion euros in 2013 relative to 2012. This difference also remains within the reliability margins.
Simplified company declarations, an adjusted definition of re-exports and a number of quality upgrades have been introduced in 2015. As a result, the international trade figures for 2015 are not completely comparable with those for 2014. The effect of this break in series is that exports for the year 2014 will be almost 10 billion euros lower and imports will be almost 9 billion euros lower. More information about this break in the series and its effect on the figures can be found in the additional survey description Oorzaken methodebreuk internationale goederenhandel, 2014-2015 (only available in Dutch).
As a result of new insights, trade flows have been revised as of the statistical year 2015. In addition to the method break 2014/2015, the total goods export is 8 billion euro lower as a result. This is 10 billion euros less for total goods imports.
The break in the trade figures between 2014 and 2015 is largely caused by an improvement in the demarcation between re-exports and quasi-transit trade. As a result, part of the imports for re-exports has been transferred to the incoming quasi-transit trade. Part of the re-exports has shifted to the outgoing quasi-transit trade.
During the whole publication period (from 2007 onwards), the same integration method has been applied. Apart from the trend breaks for specific goods flows described above, the figures can be compared easily from one year to the next. However, because of the trend breaks the figures on imports, exports, re-exports and transit trade from 2008 onwards, from 2013 onwards and from 2015 onwards may be less comparable with the corresponding figures for the previous years.
Description quality strategy
Measures taken to maximise the quality of the data are:
- The most up-to-date source data is used.
- International trade and transport figures are converted into gross weights to facilitate integration.
- At the level of trade transactions, a check is performed on the information about gross weights and transport mode.
- The Bayesian integration method guarantees consistency of figures from the separate statistics (international trade and transport statistics).
- The integrated statistics also include margins around the estimates. These margins give insight into the reliability of the figures.
- The integrated figures are tested against statistics of international trade and transport.
- The method used and the statistical results were tested against knowledge of various experts in the field of trade, transport and logistics.