Newcomers to polling sometimes assume that if you are asking Americans questions about politics, it’s only fair to include an equal number of Republicans and Democrats. While this notion makes some sense on the surface, it’s based on a misunderstanding of what polling is intended to do. The goal of a national political survey isn’t to artificially even the playing field. It’s to represent groups in their actual proportions within the country. And a wide range of evidence shows that there are more Democrats than Republicans in the United States today.
The goal of a national political survey isn’t to artificially even the playing field. It’s to represent groups in their actual proportions within the country.
But polls aren’t the only source of evidence on this question.
In the 31 states that register voters by party, the number of Americans registered as Democrats outnumbered those registered as Republicans by nearly 12 million in mid-2018. Registration with a party is an imperfect measure of whether a person currently identifies with that party, especially in the South. But nationwide comparisons find that registration is closely associated with self-identification, and the two appear to be growing more correlated over time.
In addition, commercial voter files – which attempt to predict the partisanship of voters in all 50 states and the District of Columbia based on information such as address, race, age and primary vote history – indicate that there are more Democratic registered voters than Republican registered voters in the country today.