Why public opinion polls don’t include the same number of Republicans and Democrats

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. CONT.

Courtney Kennedy & Scott Keeter, Pew Research Center