The single transferable vote (STV) is an election method that is used to obtain proportional representation. STV is used for national elections in Ireland, Northern Ireland, Malta, Australia, and New Zealand. In addition, many organizations use STV, including the Church of England and the Green Party of the United States. However, no two of the above use precisely the same definition of STV. With the same set of ballots, the above methods could produce different winners. STV can best be described as a class of election methods and users of STV must specify precisely which version of STV is to be used. The purpose of this software is to help organizations use STV and also to specify precisely which STV rules they will use.

Below, I classify and describe a variety of methods for implementing STV. The first two methods are not STV methods, but they provide a good introduction. The methods are listed roughly in order of increasing effectiveness for providing proportional representation.

The examples below will be for a hypothetical election where 99 voters are electing four candidates from a field of eight.