All about U.S. immigration statistics

The quality of data collected by the U.S. Immigration and Naturalization Service (INS) is assessed, with a focus on differences between U.S. and U.N. definitions of immigrants, emigrants, and refugees. The author suggests that "gaps in migration data collected for the U.S. limit their usefulness for studying international migration and estimating national population change. For example, no information is collected on emigration of legal permanent residents or U.S. citizens, nor is there any direct information on the immigration of U.S. citizens. Data collected on legal immigrants are based on a legal and administrative definition that often conflicts with the demographic definition of an immigrant."