International IDEA – Electoral Design System: The new International IDEA Handbook

The choice of electoral system is one of the most important institutional decisions for any democracy. In almost all cases the choice of a particular electoral system has a profound effect on the future political life of the country concerned, and electoral systems, once chosen, often remain fairly constant as political interests solidify around and respond to the incentives presented by them. The choices that are made may have consequences that were unforeseen as well as predicted effects. This guide presents the key principles of electoral system choice, the pros and cons of the options available and advice to the institutional designer.