In the recent Canadian federal election, several parties proposed changing the existing first-past-the-post (FPP) method of electing MPs to one of proportional representation. Be aware of what you wish for.
Each system of voting favours some groups or interests over others. There is no neutral system, so when a new one is proposed it usually favours a group which would earn more seats with a system different to the one in use, in this case FPP.
With FPP, the candidate with the most votes gets elected. This person might attract only 35% of the votes cast in the constituency. Since not all people vote, this would be less than 35% of total voters.
One way to address this situation is to have a system of preferential voting, whereby voters note their first, second and perhaps third choices. The winning count could then be after the subsequent choices were counted and the winner gained 50% based on first and subsequent choices. There are various formats for preferential voting which deal with some of the drawbacks of FPP. Note, what could happen in the Canadian case is that Liberals and NDP voters might give their second choice to each other, whereas the Conservatives might attract few second choices. Preferential voting works more for some than others.
Proportional representation (PR) is another voting system which receives attention. There are numerous forms that could be used, but consider the case where voters vote for a party, and where the proportion of votes received by the party is used to allocate elected representatives. In the 2015 federal election, the Conservatives, NDP, Bloc and Green parties received a higher proportion of votes cast than seats won, while it was the opposite for the Liberals. The first four might favour PR, but this ignores the fact that with PR there could be more parties putting forward candidates. In some ridings, in this election, there were up to ten party candidates on the ballot. Each party might accumulate enough votes across the country to get representation. Representation in the House of Commons would look quite different as would policy making. Where PR occurs, the legislative process leads to all sorts of tradeoffs and difficulties in governing.
My point is that while FPP has shortcomings of which we are aware because we live with them, alternative systems do not necessarily eliminate these. PR introduces other issues such as giving more influence to party officials who draw up their candidate list, and separating candidates from the ridings they represent. The actual consequences depend on the PR conditions established.
Before enacting any change, outlining its costs and benefits should be undertaken and compared with the existing system. Current discourse tends to list problems with FPP and the expected benefits of some form of PR. The benefits of FPP and the costs of PR are needed to complete the analysis.