Election Maths
Voting systems are back in the news. But what is the best option? Why should we change from what we have already? The good news is, maths can help us explore these questions. Below we have collected together some of our articles on the mathematics of elections from over the years to help you get to grips with the pros and cons. (The image on the top left shows Pip the dog waiting for everyone to finish voting. Photo by Michael de Groot, CC BY SA 2.0.)
Maths in a minute: Arrow's theorem
We start off with a rather shocking mathematical fact. In the 1950s the economist Kenneth Arrow showed that a perfect voting system doesn't exist. Find out more in this brief introduction. (For a more detailed look at Arrow's theorem, see this article.)
Elections: Three common methods
Perfection might be impossible, but we still need to vote. Here's a detailed look at three common voting methods: first past the post, proportional representation, and instant run off voting.
A quick guide to voting
Proportional representation is a tempting alternative to the first-past-the post system used in the UK. But how do you actually implement it, given that you can't split politicians up into percentages? Here's a look at some answers.
Elections: Could they be fairer?
With a bit of maths, yes! Here's a look at some more complex methods.
Another way of voting
Or should we perhaps let go of the "one person, one vote" principle? Approval voting offers a way of doing that.