Party identification is an important attitude that influences the vote (Campbell et al. 1960; Lewis-Beck et al. 2008; Green, Palmquist, and Schickler 2002). Most voters identify with one of the two major political parties, and these basic partisan loyalties influence their behavior. Party identification normally is measured by asking individuals whether they consider themselves to be a Democrat, Republican, or independent. Those indicating Democratic or Republican are asked whether they are a strong or a weak Democrat or Republican, while those claiming to be an independent are asked if they feel closer to one of the two major political parties. This yields a sevenfold classification:
- Strong Democrats
- Weak Democrats
- Independents closer to the Democrats
- Independents not closer to either party
- Independents closer to the Republicans
- Weak Republicans
- Strong Republicans
This seven-point party identification scale is in the dataset.
The influence of party identification on the vote is strong. However, not many voters in 2012 cast a ballot for Romney simply because he was a Republican or for Obama only because he was a Democrat. Rather, partisan loyalties influence evaluations of candidates, assessments of government performance, and perceptions of political events. Party identification is a perceptual screen — a pair of partisan-tinted eyeglasses through which the voter views the political world. Thus, most Republicans developed many reasons to vote for Romney, and most Democrats had many reasons to prefer Obama.