Electoral System Design: The New International IDEA Handbook

A Reynolds, B Reilly


How should electoral systems be chosen, designed and implemented? What discussion process is necessary? This handbook by the International Institute for Democracy and Electoral Assistance aims to help designers of constitutions and those involved in debate on political institutions in new and transitional democracies. It suggests criteria for deciding the best electoral system for any given context and describes the advantages and disadvantages of different systems and their possible consequences.

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 future political life. Once chosen, electoral systems remain fairly constant, as political interests solidify around and respond to the incentives they present. Much constitutional design has taken place relatively recently. The global movement towards democratic governance in the 1980s and 1990s stimulated a search for enduring models of appropriate representative institutions and a fresh evaluation of electoral systems.

Electoral systems are one of the most influential of all political institutions and of crucial importance to broader issues of governance. Some systems encourage, or even enforce, the formation of political parties; others recognise only individual candidates. Electoral systems can also influence the way parties campaign and the way political elites behave, thus helping to determine the broader political climate.

  • If an electoral system is not considered fair, losers may work outside the system, using non-democratic and even violent tactics.
  • Proportional systems are more likely to facilitate the election of small parties, and hence reduce the pressure to vote strategically.
  • A given electoral system will not necessarily work in the same way in different countries. The effects of a particular type of electoral system depend on the socio-political context in which it is used.
  • Successful electoral system design requires viewing political institutions as a whole: changing one part of the framework is likely to cause adjustments in the way other institutions within it work.
  • A presidential electoral system may complement a federal system.

In designing an electoral system, a list of important objectives should be drawn up, allowing for analysis of which electoral system would achieve them. In general, an electoral system should:

  • Provide representation and reflect the different religious affiliations, linguistic communities and ethnic groups within a society.
  • Make elections accessible and meaningful.
  • Be a means to constitute governing bodies as well as a tool for conflict management within society.
  • Facilitate stable and efficient government and hold it to account. Hold individual representatives to account.
  • Encourage political parties; promote legislative opposition and oversight.
  • Be sustainable and take international standards into account.


Reynolds, A. et al., 2005, ‘Electoral System Design: The New International IDEA Handbook’, International Institute for Democracy and Electoral Assistance, Stockholm