ALEX3: a Simulation Program to Compare Electoral Systems

he paper describes a program for comparing electoral systems based on the simulation of the preferences of the voters. The parameters requested (distribution of first preferences, district magnitude, etc) are set up by the user. The program produces the resulting Parliament under a number of electoral systems, an index of representativeness and an index of governability. The first part of the paper describes the characteristics of the program. In the second part it is used to compare eleven electoral systems in two virtual but realistic cases.