Electoral reform explained

Though electoral reform has been debated for years, the introduction of the Parliamentary Voting System and Constituencies Bill into the Commons has hardened battlelines.

Key to objections to the First Past the Post system is that support for smaller parties is spread across the country and despite a swell of support, they may never have a chance for significant representation at a national level.

All of the options can be judged by three main measures of suitability, so highlighting the inherent trade-off in each:

● Proportionality. What is the right balance between constituency representation and electing a parliament that accurately represents the national vote share?

● The likelihood of single-party government. Should the system work to increase or decrease the probability of coalition or minority government?

● The power of parties. Should a party dictate the choice of candidates, or should voters be able to pick them from within the same party?

The definitive research paper on electoral reform was published by the Independent Commission on the Voting System, chaired by Roy Jenkins, which published the Jenkins Report in December 2008. Much of the content of this graphic was taken directly from this report and a March 2010 report for the British Academy by Simon Hix, Ron Johnston and Iain McLean.

The following graphic examines the methodology, pros and cons behind each voting system and also compares the Group of 20 nations’ electoral systems. Alex Barker also provides the FT verdict on which parties would benefit from each system and which system would work best in different types of countries.