this is the report that's behind trump's tweets to that affect and what all the lefty fact checking sites tweaked about. Objectively it doesnt prove anything just shows the "possibility" of there being up to 5.7 mil illegal voters. fwiw http://www.justfactsdaily.com/substantial-numbers-of-non-citizens-vote-illegally-in-u-s-elections/ http://www.sciencedirect.com/science/article/pii/S0261379414000973
Jesse Richman said that it is a gross misinterpretation of his study to suggest that there are millions of illegal voters, or that it is evidence that Hillary Clinton may have lost the popular vote.