ABSTRACT
This chapter discusses the distinguishing characteristic of aggregate data and to avoid the most common pitfall when analyzing aggregate data. It then presents the types of aggregate data that are available, suggests some sources of the data, discusses some of the methodological problems encountered in using aggregate data, and, then offers some guidelines for collecting aggregate data. Data from each category are available on many different kinds of groups from a variety of sources. Such groups may be broadly classified into a real groups and demographic groups. Most of the aggregate data available to political scientists are gathered by non-social scientists for reasons unrelated to research. Political scientists use aggregate data to avoid becoming too focused on individuals, and to gain more general knowledge of groups or collections of persons or institutions, such as American voters, South African peasants, Russian bureaucrats, or European parliaments.
