I’d never thought about this before, but accounting for all trade and then balancing it across the border … isn’t that easy. From WaPo:
But don’t assume the import/export data we have is accurate
Critics miss a less flattering truth about trade statistics, however: Import and export data are much more messy than their champions suggest and millions of users assume.
In principle, all trade flows are recorded twice. The exporter counts when goods leave the country and the importer counts the goods when they arrive at their destination. As mirror statistics, Mexico’s exports to the United States should not differ very much from U.S. imports from Mexico. Here’s the trouble — the gap in these figures is huge, and it has been growing, rather than shrinking.
Take merchandise trade with Mexico, roughly 90 percent of total trade across the United States’ southern border, and much easier to measure than trade in services. According to the U.S. Census Bureau, the 2015 U.S. trade deficit with Mexico was $63.4 billion. The Mexican government, in contrast, put the figure roughly twice as high, at $122.1 billion (the import figures are here, the export ones here).
Makes it a little harder to plunge into international trade arguments with gusto, doesn’t it?
