Background Notes

Introduction

Goods Exports and Imports statistics provide data on the movement of goods between countries. The statistics are a combination of Customs-based non-EU trade statistics and data from the Intrastat Survey of Irish traders involved in trade with other EU member states. The collection of trade data is the responsibility of VIMA (a branch of Revenue). The CSO is responsible for processing and disseminating the data.

Revisions to the Trade in Goods statistics

Since May 2015, significant revisions were incorporated into International Trade in Goods statistics.  While the most significant revision is due to recording trade in aircraft on a "transfer of economic ownership" basis, other revisions were incorporated into the Trade data back to 2000. 

Along with the aircraft revisions Goods Exports revisions also include upward revisions due to revaluing some products that had previously been recorded on a “transfer of economic ownership” basis, which was not in line with goods statistics methodology.  Also Goods Imports revisions include downward revisions due to a change in the estimation methodology for non-response.

The technical note (http://www.cso.ie/en/methods/externaltrade/) gives more detail on the revised trade in aircraft methodology and explains the impact the revisions will have on Trade in Goods, National Accounts and Balance of Payments.

Standard Revisions

Trade figures are subject to revision on the incorporation of late Intrastat and VAT returns and corrections made by traders. When the preliminary results for a month are published, the results for months -1 (December) 2016 in this publication), -4 (September 2016) and -8 (May 2016) are revised. Following the move to a "transfer of economic ownership" basis for recording exports and imports of aircraft, SITC 79 figures are subject to revision on the incorporation of transactions from quarterly Balance of Payments (BoP) surveys. Such revisions will generally be incorporated into Goods Exports and Imports releases that coincide with quarterly BoP publications, i.e. when initial results are published for January, April, July and October.

Intrastat System

The Intrastat system has two components. Firstly, the Intrastat survey (conducted by the Revenue Commissioners), in which traders, above the Intrastat survey trade thresholds, make detailed monthly returns giving information on the quantity and value of all exports to or imports from EU countries.

The total number of traders required to make a detailed import return is around 3,500 while around 2,100 must make a detailed export return. The response rate in terms of number of traders in January 2017 was 63%, covering an estimated 82% of the total value of intra-EU trade (these response rates will have increased by the next time data for January is published).

The second component of the Intrastat system is the regular VAT return, on which all traders are required to record the total value of goods imported from and exported to other EU countries. This information provides the basis for determining total EU trade for those traders below the Intrastat survey thresholds. It is also used to maintain the register of EU traders.

Extrastat System

The statistics of trade with non-EU countries are compiled from the documents supplied by importers and exporters to the Customs authorities. The document is the Single Administrative Document (SAD) used for Customs clearance purposes.

Estimation

The figures in this release include estimates for traders above the Intrastat thresholds who did not make detailed returns for the period and for traders below the thresholds who did not provide aggregate intra-EU trade figures on their VAT returns.

Estimates for Intrastat non-respondents are apportioned to individual commodities and countries whenever previous Intrastat returns are available. Estimates for traders below the Intrastat thresholds are assigned to partner country where possible, but not to commodity.

More information is now being processed on lower value transactions. Prior to January 2012, transactions below €254 were grouped together, this value has now decreased to €127. Therefore, this has resulted in more detail being available at commodity level in Table 3 and at country level in Tables 4 and 5.

Unit Value Indices

The monthly unit value index measures monthly unit value trends relative to the annual levels in the preceding year using value weights relating to that year’s trade (Laspeyres index).

The annual index is compiled using value weights for both the current and previous year (Fisher index) to allow for change in the structure of trade in goods.

The monthly index series should be regarded as interim measures suitable for month-to-month comparisons within a given year. Previous monthly indices are revised when late returns are received.

When the annual unit value index is compiled, the monthly unit value indices are rescaled to make their average equal to the annual index.

The unit value index series has been rebased to 2010 from 1990. In the course of this rebasing, a detailed examination of the series was undertaken. This exercise has produced a number of modifications enabling production of a more robust series.

Seasonally Adjusted Series

Monthly exports, imports, trade surplus and the volume series for exports and imports have been seasonally adjusted using the US Bureau of the Census X-11 Variant of the Census Method 11 Seasonal Adjustment Program. In the main, monthly projections are based on series recalculated at the end of the previous year.

Methodology

There are methodological differences between the measurement of exports and imports in this release compared with Industrial Production, National Accounts and Balance of Payments statistics. This release records the movement of all goods over the frontier at the valuation placed on the goods at the time of crossing  the frontier. Industrial Production, National Accounts and Balance of Payments statistics take account of additional aspects of cross-frontier activities such as goods sent abroad for processing where goods cross the frontier without change of ownership. The CSO releases for those statistics provide more information on their methodology.

Services Exports and Imports

The quarterly Balance of Payments (BoP) statistics provide detail on Services exports and imports.

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