[Excerpt] Immigration projections are subject to a large degree of uncertainty even in the near term. In fact, the two agencies' projections for net migration in 2010 range, under plausible alternative assumptions, from as low as 150,000 to more than 1.5 million people. Analysis of historical data implies an 80 percent probability that over the next decade, net migration will average between about 500,000 and 1.5 million people annually, with the range of possible outcomes narrowing somewhat over a longer horizon. This paper examines the projection methodologies and outlines the most recent projections of the Social Security trustees and the Census Bureau. The trustees' projections are higher than those of the Census Bureau in the near term but lower after 2025.