Woodrow-Lafield, Karen A. 2008. Dimensions of Net Unauthorized Migration over Three Decades. Presented at the annual meeting of the Population Association of America, New Orleans, April 19.

Demographers have tracked the U.S. foreign-born population and the unauthorized share, but uncertainties persist. Component-based estimates for net legal migration are vulnerable to biases on period of arrival, inclusion of residents not yet adjusted, and accounting for return migration. These errors and any inadequacies of the foreign-born estimate affect accuracy of unauthorized migration estimates as residuals, particularly with more detailed characteristics. This presentation is an overview of research on U.S. unauthorized migration, national and state-level populations, in the context of current population programs and the 2010 census, highlighting the value of new strategies and expanded data collection.