The percentage of doctoral degree students who had firm plans to stay in the United States in 2001 was higher for Canada (58 percent) than for Mexico (38 percent), which has one of the lowest stay rates of all the major countries of origin of foreign U.S. doctoral degree recipients (figure 2-31 ).[16]

A study of U.S. doctoral degree recipients from foreign countries explored the factors affecting the decision to stay in the United States (Gupta, Nerad, and Cerny 2003). The study cited numerous factors, stressing the strength of preexisting ties to the recipients' home countries. Among the doctorate holders studied, the principal source of funding was related to their likelihood of staying in the United States: those who stayed were more likely to have been funded primarily by RAs and TAs, and those who returned to their home countries were more likely to have relied on funding from their national government or their employer.