Country example: reconciliation of the United States-Canadian current account
10.69. The United States-Canadian current account reconciliation, which explains the differences between the official bilateral statistics published by Statistics Canada and those published by the United States Bureau of Economic Analysis (BEA), is undertaken because of the extensive economic links between Canada and the United States. Reconciliation of the United States-Canadian current account was undertaken each year from 1970 to 2008, and has been carried out periodically since 2008. The reconciled estimates are intended to assist analysts who use both countries’ statistics and to show how the current account estimates would appear if both countries used common definitions, methodologies and data sources., 
10.70. Differences occur in the official statistics of the current accounts of the United States and Canada because of variations in the definitions, methodologies and sources used by each country. Some of the differences are in components of the current account for which data are preliminary and subject to revision; those differences may be reduced or eliminated when final data for those components are incorporated.
10.71. The longstanding United States-Canadian current account reconciliation is among the leading examples of the benefits of international data exchanges. As a part of the reconciliation process, Canada and the United States have evaluated the accuracy of each other's statistics and, as a result, each country now includes in its official statistics data provided by the other country. The exchange of data between Canada and the United States for such transactions as trade in goods, travel, passenger fares, Canadian and United States government transactions and some large transportation transactions covers a substantial portion of the value of the United States-Canadian current account, and has eliminated some of the differences between the official statistics of Canada and the United States. In addition, the reconciliation process has identified areas in which errors and omissions may exist, helping each country to target data improvement efforts.
10.72. Although the official statistics of Canada and the United States are reconciled, and extensive exchange of data takes place between the two countries, differences between the official statistics endure. The complete substitution of the reconciled statistics for the official statistics and a complete exchange of data are not feasible for several reasons. For some accounts, the protection of the confidentiality of the source data bars the exchange of data. In addition, a few differences are attributable to different requirements for integrating the international and domestic accounts in each country.
10.73. To reconcile the official bilateral current account statistics of Canada and the United States, the official statistics are first restated to a common basis, that is, they are adjusted for definitional and methodological differences. Next, statistical adjustments are applied to reach the reconciled values. The framework for restating the statistics to a common basis follows mainly the international guidelines published in BPM6. The official statistics of Canada and the United States now largely conform to the international guidelines, but some differences from the international guidelines, as well as between the two sets of statistics, persist because of data limitations, difficulties in determining country attribution and differences in classification. In addition, the international guidelines can sometimes provide for more than one acceptable treatment.
10.74. Definitional adjustments mainly reflect data limitations and differences in country attribution. Methodological adjustments mainly reflect differences in classification.
10.75. Statistical differences reflect the use of different source data in Canada and the United States, the difficulty of determining country attribution because of insufficient data, the preliminary nature of some data (particularly for the most recent year and the use of sample data between benchmarks. For both the northbound (United States credit transactions and Canada debit transactions) and the southbound (United States debit transactions and Canada credit transactions) statistics, most of the statistical differences are in the categories of services other than transport and travel and in the investment income accounts.
Back to C.4. Bilateral or "mirror" data
 Barbara Berman, Edward Dozier and Denis Caron, Reconciliation of the United States-Canadian Current Account, 2010 and) 2011 (United States Bureau of Economic Analysis and Statistics Canada, January 2013. Available from http://www.bea.gov/scb/pdf/2013/01%20January/0113_unitedstates-canada.pdf and http://www.statcan.gc.ca/pub/13-605-x/2013001/article/11772-eng.htm#n1.
 A detailed article on the methodology was published by the United States Bureau of Economic Analysis and Statistics Canada in "Reconciliation of the United States-Canadian Current Account" in the November 1992 Survey and by Statistics Canada in “Reconciliation of the Canadian-United States Current Account, 1990-1991”. Statistics Canada also published a shortened version in the December 1992 Canadian Economic Observer and in Canada's Balance of International Payments, third quarter 1992.
 To better understand the differences in investment income, each country’s positions on bilateral foreign direct investment and on some portfolio investment accounts are also compared during the exercise of the United States-Canadian current account reconciliation.