Transnationalism refers to the persistent ties that immigrants and their descendants have with their countries of origin. These ties can be social, such as maintaining contact with their friends and family; economic, for example, continuing to own land and businesses; or political, for instance, having an interest in, and taking part in, their country of origin's politics. Researchers characterize these transnational ties as made up of multiple attachments that stretch across national borders to make up a unified social world that is simultaneously located in two different places (Basch, Glick Schiller, and Szanton-Blanc 1994; Smith and Guarnizo 1998; Levitt and Glick Schiller 2004). Two leading immigration scholars describe how this occurs:

In this view, nation-states are seen as increasingly less relevant as an organizing principle of social interaction (Basch et al. 1994; Glick Schiller 1999; Portes 1999), facilitated by the ease of international travel and communication in an era of e-mail and Internet cafes, video-conferencing parlors in which immigrants can see and talk to the family they have left behind, instant money transfers, and cheap airfare.

Scholars generally use a few key indicators as measures of transnational ties: (1) the existence of organizational networks, such as immigrant hometown associations (Orozco 2000; Alarcón 2002; De la Garza and Hazan 2003); (2) immigrant attitudes and behaviors, such as engagement in remittance practices (i.e., immigrants sending money back to relatives in their countries of origin; Conway and Cohen 1998; Flores-Macias 2009); (3) travel back to immigrants’ countries of origin; and (4) the desire to one day live there again (Guarnizo 2000; Waldinger 2008. However, despite general agreement that the phenomenon of transnationalism exists, a number of disagreements and debates persist (Jones-Correa 2003; Waldinger and Fitzgerald 2004).