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

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 the two following 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.

The background to a choice of electoral system can thus be as important as the choice itself. One should not have the illusion that such decisions are made 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. At the same time, the choices of available electoral systems are often, in reality, relatively few. 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 recognising the practical constraints, we attempt to approach the issue of electoral system choices in as broad and comprehensive manner as possible.

The electoral system element of this publication 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, the text 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 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.

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

Electoral Systems and Constitutions

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, along with a fresh evaluation of electoral systems. This process has been encouraged by the widespread realisation 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' cooperation 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.

Through providing this detailed analysis of choices and consequences, and showing how electoral systems have worked throughout the democratic world, we hope to achieve two things:

• to expand knowledge and illuminate political and public discussions;
• and to give constitutional designers the tools to make an informed choice, and thereby avoid some of the more dysfunctional and destabilizing effects of particular electoral system choices.

At the most basic level, electoral systems translate the votes cast in a general election into seats won by parties and candidates. The key variables are 1. the electoral formula used (i.e., whether the system is majoritarian or proportional, and what mathematical formula is used to calculate the seat allocation) and 2. the district magnitude, not how many voters live in a district, but rather how many members of parliament that district elects.

Electoral system design relates strongly to the other more administrative aspects of elections dealt with on this web site such as the distribution of voting places (see Voting Operations), the nomination of candidates (see Parties and Candidates), the registration of voters (see Voter Registration), who runs the elections and so on - see Electoral Management. These issues are of critical importance, and the possible advantages of any given electoral system choice will be undermined unless due attention is paid to them. Electoral system design also affects other areas of electoral laws: the choice of electoral system has an influence on the way in which district boundaries are drawn (see Boundary Delimitation), the design of ballot papers (see Voting Operations), how votes are counted (see Vote Counting), along with numerous other aspects of the electoral process.

Summary of Electoral System Types

There are hundreds of electoral systems currently in use and many more permutations on each form, but for the sake of simplicity we have categorised electoral systems into three broad families:

• the plurality-majority,
• the semi-proportional, and
• the proportional.

Within these three we have ten 'sub-families':

• First Past the Post (FPTP),
• the Block Vote (BV),
• the Alternative Vote (AV), and
• the Two-Round System (TRS) are all plurality-majority systems.
• Parallel systems,
• the Limited Vote (LV) and
• the Single Non-Transferable Vote (SNTV) are semi-proportional systems.
• List PR,
• Mixed Member Proportional (MMP), and
• the Single Transferable Vote (STV) are all proportional systems.

Every one of the 212 parliamentary electoral systems listed in The Global Distribution of Electoral Systems can be categorised under one of these ten headings, and this family tree, though rooted in long-established conventions, is the first to take account of all the electoral systems used for parliamentary elections in the world today, regardless of wider questions of democracy and legitimacy. We hope it offers a clear and concise guide to the choice among them.

The most common way to look at electoral systems is to group them by how closely they translate national votes won into parliamentary seats won; that is, how proportional they are. To do this, one needs to look at both the vote-seat relationship and the level of wasted votes. For example, South Africa used a classically proportional electoral system for its first democratic elections of 1994, and with 62.65% of the popular vote the African National Congress (ANC) won 63% of the national seats (see South Africa: Election Systems and Conflict Management). The electoral system was highly proportional, and the number of wasted votes (i.e., those which were cast for parties which did not win seats in the Assembly) was only 0.8% of the total. In direct contrast the year before, in the neighbouring nation of Lesotho, a classically majoritarian First Past the Post (FPTP) electoral system had resulted in the Basotho Congress Party winning every seat in the 65-member parliament with 75% of the popular vote; there was no parliamentary opposition at all, and the 25% of electors who voted for other parties were completely unrepresented. This result was mirrored in Djibouti's Block Vote election of 1992 when all 65 parliamentary seats were won by the Rassemblement Populaire pour le Progres with 75% of the vote.

However, under some circumstances, non-proportional electoral systems (such as FPTP) can accidentally give rise to relatively proportional overall results. This was the case in a third Southern African country, Malawi, in 1994. In that election the leading party, the United Democratic Front won 48% of the seats with 46% of the votes, the Malawian Congress Party won 32% of the seats with 34% of the votes, and the Alliance for Democracy won 20% of the seats with 19% of the votes. The overall level of proportionality was high, but the clue to the fact that this was not inherently a proportional system, and so cannot be categorized as such, was that the wasted votes still amounted to almost one-quarter of all votes cast.

For more information see Electoral Systems and Constitution.