Introduction

International migration appears at the present time to be at or near historically high levels (Organization for Economic Co-operation and Development [OECD], 2005), but the illegal component is the most perplexing to receiving nations and the component that probably has increased most in recent years. Much illegal migration is from less- to more-developed countries and presents serious challenges in migrant-receiving nations. The first problem is that whereas the illegals may be known to be present, in some cases in large numbers, even approximate estimates of their actual numbers are difficult to obtain (Espenshade, 1995; Bean et al., 1998; Tapinos, 1999; Hanson, 2006). Thus, the discussion of their effects and what to do about them is not grounded in substantive data.

Where illegal migrants and/or their children qualify for social benefits or education, social programs and educational systems may be stressed as transfers occur from indigenous residents to migrants. Ethnic tensions may rise as cultures clash. Those migrants who do not speak the receiving country's primary language often have difficulty assimilating, and some of these problems may spill over into the educational system through higher costs of bi-lingual education and in other ways. In many cases, citizenship may not be available or may be possible only after a long wait, which leaves a potentially large group disenfranchised.

Figure 23.1 reports the percentages of population that were foreignborn circa 1993 and circa 2002 in selected OECD countries.