The International Trade Division (ITD) of Statistics Canada produces monthly preliminary estimates of International Merchandise trade on both a Customs and Balance of Payments (BOP) basis along with the associated price and volume indices. These estimates are prepared under very tight deadlines and depend primarily on large volumes of administrative records received from the Canadian Border Services Agency and the United States Customs Border Protection Agency. In accordance with the agreement on the exchange import data, Canadian and United States international merchandise trade data are released simultaneously by Statistics Canada and the United States Census Bureau roughly 42 days after the end of the reference month.
In addition to being a closely watched indicator in its own right, merchandise trade data are a critical input to the System of National Accounts and are prepared in accordance with the System of National Accounts concepts, definitions, and revision schedule in mind. While the Customs data are available on the day of release, it is the seasonally adjusted BOP based data series, along with the associated price and volume indices, that are the focus of our monthly release in the Daily.
Following the release, revisions are made to account for the late receipt of import and export documentation, incorrect information on Customs forms, replacement of estimates with actual figures, changes in classification of merchandise based on more current information, and changes to seasonal adjustment factors. The revision process aims to strike a balance between, on the one hand, keeping the published database as accurate and up-to-date as possible and on the other hand, managing the workflow and keeping the flow of information to our clients as orderly as possible.
In general, merchandise trade data are revised on an ongoing basis for each month of the current year. Current year revisions are reflected in both the Customs and BOP based data. The previous year’s Customs data are revised with the release of the January and February reference months as well as on a quarterly basis. The previous two years of Customs based data are revised annually and are released with the December reference month. The previous year’s BOP based data are revised with the release of the January, February and March reference months. Revisions to BOP based data for the previous three years are released annually in June with the April reference month.
Factors influencing revisions include late receipt of import and export documentation, incorrect information on customs forms, replacement of estimates produced for the energy sector with actual figures, changes in classification of merchandise based on more current information, and changes to seasonal adjustment factors.
Seasonal Adjustment - Both export and import statistics show large monthly fluctuations. In order to isolate turning points or trends in the basic data, it is necessary to eliminate this effect of seasonal movement. Statistics Canada uses the X-11-ARIMA (Dagum, 1975 and 1979) method to remove seasonal fluctuations from time series.
Revised data are available in the appropriate CANSIM tables.