The United States is one of the few countries in the world that uses political primaries to choose who will represent major political parties in general elections. Decade after decade, turnout in primaries lags well behind turnout in general elections. The small size of most primary electorates, the fact that some states limit participation to registered members of a political party thus decreasing the potential pool of voters even further, and the often low or near invisible press coverage of so many primaries means that, in contrast to other elections, primaries receive little attention from either press or scholars. Congressional primaries nonetheless have a profound impact on policymaking in the United States. A better understanding of their outcomes is essential to understanding modern American politics.
For that reason, in 2014, the Center for Effective Public Management established The Primaries Project. Researchers associated with the project have closely examined congressional primaries in the 2014, 2016, and 2018 election cycles, placing an emphasis on understanding who runs—and who wins—in these races. In 2016, the project expanded to include a first-of-its-kind exit poll for congressional primaries, leading to unprecedented analysis of who votes in Congressional primaries, and whether they differ significantly from general election voters.