Preelection poll accuracy and bias in the 2016 U.S. general elections

This report examines accuracy and bias in national- and state-level preelection polls conducted during the 2016 U.S. general election cycle. Overall, national polls in 2016 were somewhat more accurate than in 2012, but statewide polls were less accurate. Patterns across the board suggest polls underestimated Republican support in the presidential, U.S. Senate and gubernatorial races. Nevertheless, these biases were generally statistically insignificant, suggesting significant bias in preelection polls was scarce in 2016.