CPO-STV, or the Comparison of Pairs of Outcomes by the Single Transferable Vote, is a preference voting system designed to achieve proportional representation. It is a highly sophisticated variant of the Single Transferable Vote (STV) system, designed to overcome some of that system's perceived short-comings. As in other forms of STV, in a CPO-STV election more than one candidate is elected and voters must rank candidates in order of preference. It is a relatively new system and hasn't yet been… (More on Cpo-stv)