Written by Tim Haughton (University of Birmingham), this chapter of A Political Science Experiment explores the following questions:

– What is a political party?
– What are the functions and roles of political parties?
– What are the different types of political parties, and how are they organized?
– Where does power lie in political parties?
– What are the ideological differences between political parties?
– What do we mean by “left” and “right,” and how helpful are they when describing political parties?
– What role do historical, sociological, and institutional factors play in shaping party systems?
– How can we measure the differences between party systems?
– Why do some parties survive for longer than others?
– What explains the emergence of new or challenger parties?