Revisions to international merchandise trade statistics
This is an update to the 2009 article Revisions to international merchandise trade statistics, accounting for changes resulting from increased timeliness in the release of merchandise trade statistics.
Monthly international merchandise trade statistics are now available five days earlier than previously—on average, 35 days after the end of the reference month. These data are incorporated into the quarterly Gross Domestic Product by Income and by Expenditure Accounts (IEA), approximately 60 days after the end of the reference quarter, at which point they are subject to revision. This note outlines the primary sources of the revisions.
Current dollar revisions
In current dollars, revisions are often made to energy data after the monthly international merchandise trade statistics have been published. For exports of crude oil and natural gas, and imports of crude oil, there are two sources of volume information, namely customs data and energy surveyNote 1 data. The energy survey data better reflect the month in which the transactions occur and are also consistent with other energy survey data on supply and demand. However, not all the energy survey data are available in time for the monthly publication of international merchandise trade. When the IEA are being calculated, more up-to-date energy survey data become available and are included in the estimates of international merchandise trade and gross domestic product (GDP).
In addition to more timely energy data, there may be revisions to the published monthly international merchandise trade arising from the balancing of the quarterly IEA or the availability of revised customs data. Furthermore, in the first quarter of the year, there are revisions to IEA’s international trade data arising from the annual revision of the national accounts. These primarily include revised seasonal patterns and new estimates for under-coverage of exports. The release of the Income and Expenditure Accounts’ annually revised data precedes the revision of the monthly International Merchandise Trade Statistics by one week, when similar data are published.
Constant dollar revisions
In the constant dollar series there are additional revisions arising from changes to the adjustments made to trade price indexes, which are captured in the ‘other balance of payments adjustments’ trade series.
Aggregate international trade price adjustments are re-calculated during the quarterly production of the IEA, as relevant information becomes available. The adjustments included during the production of monthly international merchandise trade are typically forecasts based on historical rates, and at times can differ from final values derived when more complete information becomes available.
Finally, an important part of the construction of the IEA is an extensive economy-wide coherence analysis through supply and disposition models and comparisons between data sources—exports and production for example. At times, based on this analysis, it is necessary to adjust international merchandise trade either at the commodity or aggregate level.
- Crude oil production data are provided by the producing provinces through the following surveys: Crude Oil and Natural Gas; crude oil exports are picked up from our pipeline survey: Monthly Oil Pipeline Transport; crude oil imports from the Monthly Refined Petroleum Products; natural gas exports: partially from the National Energy Board; and natural gas exports data from the monthly Gas Utilities/Transportation and Distribution Systems.
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