Abstract: How do we measure phenomena that cannot be directly observed? The principal aim of this paper is to demonstrate why factor analysis technique is the best answer to this question. Methodologically, we use a database with different indicators of democracy to show how principal component analysis can be employed to measure the two polyarchy dimensions proposed by Robert Dahl (1971): contestation and inclusiveness. On substantive grounds, we hope to facilitate the understanding of factor analysis technique in Social Sciences in general and in Political Science in particular.
factor analysis; democracy; polyarchy; measurement; quantitative methods
