The International IDEA Handbook of Electoral System Design

Publication Date: 
31 Dec 2001

Publication Type:



1. The choice of electoral system is one of the most important institutional decisions for any democracy, yet only rarely are electoral systems consciously and deliberately selected. Often the choice is essentially accidental, the result of an unusual combination of circumstances, of a passing trend, or of a quirk of history, with the impact of colonialism and the effects of influential neighbours often especially strong. Yet 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 in most cases electoral systems, once chosen, remain fairly constant as political interests congeal around and respond to the incentives presented by them.

2. If it is rare that electoral systems are deliberately chosen, it is rarer still that they are carefully designed for the particular historical and social conditions of a country. Any new democracy must choose (or inherit) an electoral system to elect its parliament, but such decisions are often affected by one of two circumstances. Either political actors lack basic knowledge and information so that the choices and consequences of different electoral systems are not fully recognized or, conversely, political actors use their knowledge of electoral systems to promote designs which they think will work to their own partisan advantage. In either scenario, the choices that are made may not be the best ones for the long-term political health of the country concerned, and at times they can have disastrous consequences for a country’s democratic prospects.

3. The background to a choice of electoral system can thus be as important as the choice itself. We are under no illusions that such decisions are taken in a political vacuum. In fact, the consideration of political advantage is almost always a factor in the choice of electoral systems – sometimes it is the only consideration – while the menu of available electoral system choices is often, in reality, a relatively constrained one. It is equally the case, however, that calculations of short-term political interest can often obscure the longer-term consequences of a particular electoral system and the interests of the wider political system. Consequently, while recognizing the practical constraints, we attempt to approach the issue of electoral system choices discussed in this handbook in as broad and comprehensive a manner as possible.

4. This handbook is aimed in particular at political negotiators and constitutional designers in new, fledgling, and transitional democracies. However, as the crafting of political institutions is a critical task not only for new democracies but also for those established democracies seeking to adapt their systems to better reflect new political realities, this handbook also seeks to address the likely concerns of those persons in both emerging and established democracies who may be designing electoral systems. Given this target audience, we have necessarily had to simplify much of the academic literature on the subject, while at the same time attempting to address some of the more complex issues inherent in the area. If we appear to be sometimes overly simplistic and at other times unduly complex, the explanation will usually lie in our attempt to balance these two objectives of clarity and comprehensiveness.

5. While the context in which emerging and established democracies make constitutional choices can vary enormously, their long-term purposes are usually the same: to adopt institutions which are strong enough to promote stable democracy but flexible enough to react to changing circumstances. Both types of democracy have much to learn from the experiences of the other. Institutional design is an evolving process, and this handbook seeks to distil the lessons learnt from the many actual examples of institutional design around the world.

6. Much constitutional design has occurred relatively recently: the world-wide movement towards democratic governance in the 1980s and 1990s stimulated a new urgency in the search for enduring models of appropriate representative government, and a fresh evaluation of electoral systems. This process has been encouraged by the widespread realization that the choice of political institutions can have a significant impact upon the wider political system – for example, it is increasingly being recognized that an electoral system can help to “engineer” co-operation and accommodation in a divided society. Electoral system design is now accepted as being of crucial importance to wider issues of governance, and as probably the most influential of all political institutions.

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