r/EndFPTP

Mixed Transferable Vote (MTV) is a voting system that uses a ranked ballot to elect constituency MPs and a smaller number of regional/national top-up MPs to get better proportionality. It beats STV for proportionality and allows a mixture of small and large constituencies including single-member constituencies. Proportionality should be very good for major and medium-sized parties whilst having a soft threshold against micro-parties. Constituency counting does not require calculation of fractional surplus votes and the quota is the same in every constituency. It should be highly resistant to tactical voting and tactical nomination.

Constituencies are allocated a number of MPs such that v/(n+1) is minimised but still greater than q - where v is the number of voters in a constituency, n the number of MPs for that constituency and q a quota chosen to be approximately the national population divided by the number of MPs in parliament (it may be varied to change the ratio of constituency to top-up MPs).

The first stage of counting in each constituency is done by eliminating the last placed candidate and transferring their votes to the next-placed candidate on each ballot. This process continues until the number of candidates remaining is equal to the number to be elected plus one. Unlike STV, votes for candidates exceeding quota are not redistributed in this first stage but pooled together in a second stage in which candidates are elected from an open party list.

To calculate the surplus votes first take the national quota q (eg 80,000) and multiply it by an expected national turnout figure (eg 70%). In this example we get a figure of 56,000. In each constituency if a candidate exceeds 56,000 votes in the final round then the excess is transferred to the top-up round. If a candidate wins with less than 56,000 then zero is transferred. The last-remaining losing candidate has all their final-round votes transferred.

The second stage allocates seats to open party lists using the Sainte-Lague/Webster method of apportionment. It can be carried out at a national level or at a regional level to ensure proportional representation for each region. The open lists are drawn up by ranking candidates for each party by their first-round constituency vote. Independent candidates are considered as parties with only one candidate. Should a party run out of candidates on the top-up list then the seat is allocated to another party. The top-up process could prefer female candidates to encourage gender-parity. Top-up MPs will represent the constituency for which they stood in the first round.