Majoritarian and consensual democracies: The seat product connection

Abstract

This study connects two apparently disparate fields of inquiry in a specific quantitative way. In Lijphart’s Patterns of Democracy, the majoritarian–consensual “executives–parties” score (L) combines five indices. Four of these largely or entirely derive from factors that Shugart and Taagepera, Votes from Seats, logically deduced from the product of two numbers: the number of seats in an average electoral district (M) and in the first or only chamber of representative assembly (S). Hence L connects to the purely institutional seat product MS (logged) along a simple logistic pattern. It can be predicted from $L\hspace{0.17em}=\hspace{0.17em}\frac{4}{1+35{\left(MS\right)}^{-0.56}}-2$ , with R² = 0.59. Thus, surprisingly, the majoritarian–consensual typology largely stems from the number of seats available.