"This report reviews estimates of fiscal impacts to the federal, state, and local governments of the foreign born who reside in the United States. It examines the academic and policy literature on fiscal impacts of two populations: all U.S. foreign born and unauthorized aliens. Computing such fiscal impacts involves numerous methodological and conceptual challenges, and resulting estimates vary considerably according to the assumptions used, including those about the time frame considered, the treatment of U.S.-born children, the unit of analysis used, and which costs and revenues are included. […] Three national estimates evaluated in a 1995 General Accounting Office (GAO) report varied considerably and left the agency unable to definitively quantify such fiscal impacts. Subsequent state-level studies emphasized fiscal impacts of costly public services: public education, health care, and law enforcement. Many estimated tax and other fiscal contributions. Studies estimating fiscal impacts for unauthorized aliens are more likely to yield estimated net fiscal deficits than those estimating fiscal impacts for all foreign born, because unauthorized aliens, on average, tend to be younger and less educated. Consequently, they are more likely to use public education for their children and contribute relatively less in tax revenues compared to all foreign born. Given their unauthorized status, they are also less likely themselves to receive public benefits, although their U.S.-born children may be more likely to qualify for such benefits. However, deriving more specific conclusions or estimates from studies of unauthorized aliens reviewed in this report remains elusive due to variation in study design and methodology."
CRS Report for Congress, R42053