Over the course of the next several weeks, there will be many national and state surveys released. In order to help people make sense of this data, we have compiled party identification and ideology results from exit polls in recent elections.
Exit polls are a unique set of numbers, as they are the only major dataset that is directly weighted to election results. That unique quality gives them the reputation of being the “official record” of what happened in an election.
When evaluating a poll, it’s important to take partisan breakdown into account. A survey that dramatically overstates the number of Republicans or Democrats likely to turn out may not give an accurate read on public opinion among the true electorate. For example, the margin between Democrats and Republicans was at its largest since 1984 during the 2008 election. That year, the number of Democrats was larger than the number of Republicans by 7 points — quite a change from 2004 when things were even. The partisan breakdown in Midterm election years is always different from presidential elections, but we include them in our national data here for historical reference.
Ideological makeup is also important. Often, the words “center-right” are used to describe the American electorate. This chart reflects that, as moderates have generally comprised the largest group, with conservatives significantly outnumbering liberals.
As a resource, we have compiled breakdowns by party identification and ideology for the period 1984-2008 at the national level and across the previous four general elections (1996-2008) for the 50 states and the District of Columbia. That information is available on our website, here. We hope this will provide the public with a metric for evaluating polls as they’re released between now and Nov. 6.