Our data comes from the Cooperative Congressional Election Study (CCES). Its large number of observations (32,800 in 2008 and 55,400 in 2010) provide sufficient samples of the non-immigrant sub-population, with 339 non-citizen respondents in 2008 and 489 in 2010. For the 2008 CCES, we also attempted to match respondents to voter files so that we could verify whether they actually voted.
How many non-citizens participate in U.S. elections? More than 14 percent of non-citizens in both the 2008 and 2010 samples indicated that they were registered to vote. Furthermore, some of these non-citizens voted. Our best guess, based upon extrapolations from the portion of the sample with a verified vote, is that 6.4 percent of non-citizens voted in 2008 and 2.2 percent of non-citizens voted in 2010.
Estimated Voter Turnout by Non-Citizens
2008 2010
Self reported and/or verified 38 (11.3%) 13 (3.5%)
Self reported and verified 5 (1.5%) N.A.
Adjusted estimate 21 (6.4%) 8 (2.2%)
source..Washington post
http://projects.iq.harvard.edu/cces/home
http://www.sciencedirect.com/science/article/pii/S0261379414000973
Abstract
In spite of substantial public controversy, very little reliable data exists concerning the frequency with which non-citizen immigrants participate in United States elections. Although such participation is a violation of election laws in most parts of the United States, enforcement depends principally on disclosure of citizenship status at the time of voter registration. This study examines participation rates by non-citizens using a nationally representative sample that includes non-citizen immigrants. We find that some non-citizens participate in U.S. elections, and that this participation has been large enough to change meaningful election outcomes including Electoral College votes, and Congressional elections. Non-citizen votes likely gave Senate Democrats the pivotal 60th vote needed to overcome filibusters in order to pass health care reform and other Obama administration priorities in the 111th Congress.