Undocumented Immigration

One important characteristic that distinguishes contemporary immigration from previous waves of immigration is the presence of significant numbers of undocumented, or illegal, immigrants. The dearth of sound information on undocumented immigrants makes formulating and implementing policy concerning this clandestine segment of the population extremely difficult. The first part of this article presents up-to-date empirical studies of the numbers of undocumented aliens in the country. The principal conclusion to be drawn from these studies is that the size of the undocumented immigrant population is substantially smaller than the figures most often cited. Although the largest numbers of undocumented immigrants are from Mexico, virtually every area of the world contributes some undocumented immigrants. The available evidence regarding the social, economic, and demographic characteristics of undocumented immigrants is reviewed in this article. The various arguments concerning the economic and social consequences of undocumented immigration are reviewed, together with the contradictory evidence used to support them. Finally, the consequences of research findings for policy alternatives are presented and various options for dealing with undocumented immigration are discussed.