The single transferable vote (STV) is a voting method that allows voters to rank candidates in order of preference. Voters cast a single vote, and their vote is transferred to their next-preferred candidate if their first-choice candidate is eliminated.

In first-past-the-post voting, a candidate must win a majority of votes in order to be elected. In plurality voting, a candidate only needs to win the most votes in order to be elected, even if they do not win a majority.

The United States presidential election uses the electoral college system, in which each state is allocated a certain number of electoral votes based on its population. The candidate who wins the most electoral votes becomes president, even if they do not win the popular vote.

Proportional representation voting systems are designed to ensure that all parties are represented in the legislature in proportion to their share of the vote. This means that even small parties can win seats in the legislature, which can lead to a more diverse and representative government.

Australia uses a preferential voting system, in which voters rank candidates in order of preference. If no candidate wins a majority of first-preference votes, then the candidate with the fewest first-preference votes is eliminated and their votes are transferred to their next-preferred candidate. This process continues until one candidate wins a majority of votes.

Plurality voting is often criticized for leading to a two-party system, because it is difficult for third parties to win elections under this system. This can lead to a lack of diversity and competition in the political system.

New Zealand uses a mixed-member proportional representation system, which combines elements of first-past-the-post and proportional representation. Voters cast two votes: one for a local candidate in their electorate, and one for a party list. The seats in the legislature are then allocated based on the proportion of votes that each party receives.

First-past-the-post voting is often praised for producing clear and decisive results. Under this system, the candidate who wins the most votes in each district is elected, which makes it easy to determine who has won the election.

Canada uses a first-past-the-post voting system, in which the candidate who wins the most votes in each riding is elected. This system is often criticized for leading to a two-party system, because it is difficult for third parties to win elections under this system.

Proportional representation voting systems can lead to a more fragmented legislature, because multiple parties are likely to win seats in the legislature. This can make it difficult for governments to form stable majorities, which can lead to political instability.

Germany uses a mixed-member proportional representation system, which combines elements of first-past-the-post and proportional representation. Voters cast two votes: one for a local candidate in their constituency, and one for a party list. The seats in the Bundestag (the German parliament) are then allocated based on the proportion of votes that each party receives.

Instant-runoff voting is designed to ensure that the winner has the support of a majority of voters. Under this system, voters rank candidates in order of preference. If no candidate wins a majority of first-preference votes, then the candidate with the fewest first-preference votes is eliminated and their votes are transferred to their next-preferred candidate. This process continues until one candidate wins a majority of votes.

Ireland uses a single transferable vote system, in which voters rank candidates in order of preference. If no candidate wins a majority of first-preference votes, then the candidate with the fewest first-preference votes is eliminated and their votes are transferred to their next-preferred candidate. This process continues until one candidate wins a majority of votes.

First-past-the-post voting is often criticized for leading to a two-party system, because it is difficult for third parties to win elections under this system. This can lead to a lack of diversity and competition in the political system.

France uses a two-round system, in which voters cast two votes: one in the first round and one in the second round. If no candidate wins a majority of votes in the first round, then the top two candidates advance to the second round. The candidate who wins the most votes in the second round is elected president.