This chapter focuses on the measurement of positive partisanship. For that purpose, I introduce the reader to the (positive) partisan identity scale that captures crucial components of partisan identity such as partisans’ sense of belonging to the in-party, feeling connected to other party members, as well as the emotional significance of the party membership.

In this chapter, I offer a thorough review of the scholarship that investigates the impact of partisan identity (i.e., expressive partisanship) on political behavior, including political attitudes, turnout, voting, and other forms of political participation.

In this chapter, I introduce instrumental and expressive partisanship as well as its their different predictions for political behavior.

I introduce a multi-item index that captures negative partisan identity. Utilizing this new scale, I demonstrate the magnitude of negative partisan identity among the electorate in the United States and in four European multi-party systems.

Much of the modern study of mass political behavior in the United States often returns to three books released during the Eisenhower administration. Voting by Berelson, Lazarsfeld, and McPhee (1954) approached its subject from a sociological perspective. Anthony Downs’ (1957) An Economic Theory of Democracy is the foundational study of political decision-making from the rational-choice perspective. The American Voter by Campbell et al. (1960) pioneered the use of the mass survey for political research. These approaches to studying politics are ubiquitous now, but, at the time, these were pathbreaking methodological advances. The authors of these books were to the study of politics what Chuck Berry, Little Richard, and Elvis Presley were to popular music.