Predicting Party Sizes ― The Logic of Simple Electoral Systems

For a given electoral system, what average number and sizes of parties and government duration can we expect? Predicting Party Sizes is the first book to make specific predictions that agree with world averages. The basic factors are the numbers of seats in the assembly and in the average electoral district. While previous models tell us only the direction in which to change the electoral system, the present ones also tell us by how much they must be changed so as to obtain the desired change in average number of parties and cabinet duration. Hence, combined with known particularities of a country, they can be used for informed institutional design.

The book is useful to three types of readers: political science students learning the basics of electoral systems and their political consequences; practitioners of politics who consider changing the electoral laws; and researchers intent on connecting electoral and party systems. The book is structured accordingly. Chapters start with advice and recipes for practicing politicians, in non-technical language. The main text gives students an overview of electoral systems, worldwide, and supplies evidence for models that tie simple electoral systems (First-Past-The-Post and List Proportional Representation) to the number and sizes of parties and government duration. Chapter appendices present derivations of these models and other more technical issues of interest to researchers.

Born in Tartu, Estonia, 1933, Rein Taagepera became a war refugee in 1944, completed Estonian-language grade school in Germany and French-language high school in Morocco. He has B.A.Sc in engineering physics and M.A. in physics (University of Toronto), and Ph.D. in solid state physics and M.A. in international relations (University of Delaware. After 6 years of industrial research at DuPont Co., he has taught political science at University of California, Irvine since 1970 and also at University of Tartu, Estonia since 1992. He ran third in Estonia's presidential elections 1992, and was in 2001 the founding chair of a political party that later won the elections. He has over 100 research articles in electoral studies and comparative politics, Baltic area studies, Finno-Ugric linguistics, and physics. His books include Seats and Votes (with Matthew Shugart), The Baltic States: Years of Dependence 1940-1990 (with Romuald Misiunas), and The Finno-Ugric Republics and the Russian State.