FPTP: you get one vote, and each constituency elects one representative. Whoever has the most votes in each constituency wins, every other candidate in the constituency gets nothing.
AMS: Like FPTP, but with an extra layer of regional elections. The results of the regional are weighted towards parties that got a lower number of seats in the FPTP section than their share of the votes (so a party that comes second or third a lot but rarely wins in FPTP will do well). This isn’t completely proportional, but it does shift the results a bit towards proportionality and makes it so that votes for non-winning candidates still have some effect.
STV: Instead of voting for one person, you rank the available choices. The candidate with the fewest first-preference votes is eliminated, and that candidates votes are given to their second preference. This repeats until someone gets a majority. This reduces the pressure of tactical voting compared to FPTP, because you can pick a first preference even if you don’t expect them to win and a lower preference as your “well at least it’s not the other big party that I dislike more” as a backup
Party list PR: Each party is given a number of seats equal to their share of the national vote. The party’s most popular candidates in each constituency get seats first (so results will tend towards candidates that are popular in each area, though not strictly. This sacrifices local representation for maximum proportionality
The UK’s general elections are currently FPTP. The Scottish Parliament and Welsh Senedd use AMS, the Northern Irish Assembly uses STV, and the UK used Party List PR for EU elections prior to Brexit
FPTP: you get one vote, and each constituency elects one representative. Whoever has the most votes in each constituency wins, every other candidate in the constituency gets nothing.
AMS: Like FPTP, but with an extra layer of regional elections. The results of the regional are weighted towards parties that got a lower number of seats in the FPTP section than their share of the votes (so a party that comes second or third a lot but rarely wins in FPTP will do well). This isn’t completely proportional, but it does shift the results a bit towards proportionality and makes it so that votes for non-winning candidates still have some effect.
STV: Instead of voting for one person, you rank the available choices. The candidate with the fewest first-preference votes is eliminated, and that candidates votes are given to their second preference. This repeats until someone gets a majority. This reduces the pressure of tactical voting compared to FPTP, because you can pick a first preference even if you don’t expect them to win and a lower preference as your “well at least it’s not the other big party that I dislike more” as a backup
Party list PR: Each party is given a number of seats equal to their share of the national vote. The party’s most popular candidates in each constituency get seats first (so results will tend towards candidates that are popular in each area, though not strictly. This sacrifices local representation for maximum proportionality
The UK’s general elections are currently FPTP. The Scottish Parliament and Welsh Senedd use AMS, the Northern Irish Assembly uses STV, and the UK used Party List PR for EU elections prior to Brexit