According to the Department of Homeland Security Yearbook of Immigration Statistics, in fiscal year 2006 (October 2005 – September 2006), 73,880 foreign skilled workers (64,633 Canadians and 9,247 Mexicans) were admitted to the United States for temporary employment under NAFTA (i.e., TN status). In addition, 17,321 family members (13,136 Canadians, 2,904 Mexicans and a number of third-country nationals married to Canadians and Mexicans) entered the United States under Contracting Country (TD) status.  Since DHS counts the number of new I-94 arrival records completed at the border and TN-1 approval is valid for three years, the number of non-immigrants with TN status present in the United States at the end of the fiscal year approximates the number of registrations during the year. (A discrepancy may be caused by the fact that some TN participants leave the country or change status before the expiry of their three-year admission period, while other previously admitted immigrants may change their status to TN or TD or renew previously granted TN status.) In 2009, the United States recorded a trade surplus of $28.3 billion with NAFTA countries for services and a trade deficit of $94.6 billion (annual increase of 36.4%) for goods in 2010. This trade deficit accounted for 26.8% of the total U.S. trade deficit.  A study on global trade, published in 2018 by the Center for International Relations, identified irregularities in the trade models of the NAFTA ecosystem using networked analysis techniques. The study showed that the US trade balance has been influenced by opportunities for tax evasion in Ireland.  Trade pacts are often politically controversial, as they can change economic practices and deepen interdependence with trading partners. Improving efficiency through «free trade» is a common goal. Governments largely support other trade agreements.
As a result, Uruguay Round negotiators developed the Agreement on Trade-Related Investment Measures (TRIMs), which essentially clarifies Gatt Articles III and XI, including by inserting a short illustrative list of practices prohibited by these Articles. For example, trims is a flagrant violation of the rules when an investor requires it to use domestic rather than imported products, or a company restricts the use of imported products to the value of local products exported. In its May 24, 2017 report, the Congressional Research Service (SIR) wrote that the economic impact of NAFTA on the U.S. economy was modest. In a 2015 report, the Congressional Research Service summarized several studies as follows: «In reality, NAFTA did not cause the huge job losses that critics feared or the significant economic benefits predicted by supporters. The overall net effect of NAFTA on the U.S. economy appears to have been relatively modest, mainly because trade with Canada and Mexico represents a small percentage of the U.S. . . .