How are ballots counted with STV? Watch these 4 videos
How the Ballots are Counted: The Simple Way
STV is a proportional system where voters elect a team of local
and regional MPs using a ranked ballot.
The easiest way to count the ballots is just like the run-off vote that
political parties use to elect their leaders.
Voters rank their preferred candidates - as few or as many as they
wish. The candidate with the fewest first preferences is eliminated
and those ballots transferred to the next choice on each ballot.
This is repeated until there are only as many candidates left as
In rural ridings electing just one MP, this is also how the votes
will be counted.
This simple method of using STV - multi-member instant run-off
voting - produces the same results as the method below with the
extra steps 97% of the time.
How the votes are usually counted in a multi-member riding:
To get elected to one of the seats on the team, a candidate would
need a certain quota of votes.
This number needed to get a seat (the quota) will depend on how
many voters there are, and how many seats there are.
You can figure out the quota for your riding by taking the total
number of ballots cast, divided by the number of MPs to be
elected plus one, plus an additional one.
So, if there are 100 voters and 4 candidates to be elected, each
MP would need 21 votes. (100 / 4+1) + 1 = 21). Watch
the videos above and try STV here..
All you really need to know:
In a five seat district, a candidate would need about 16% of first-choice votes to be elected, although in some cases the last MP to fill a seat will be elected with less than a full quota (as low as 10%). In a riding with more MPs, that threshold would be lower. In a riding with fewer MPs, that threshold would be higher.
Part Two Below:
From the perspective of the voter, STV is straightforward. Candidates are listed alphabetically on the ballot paper, and voters mark their first choice candidate with the number 1, and then continue to rank other candidates in order of choice (2, 3, 4...).
These preferences are transferred from one candidate to another as
the ballots are counted.
While each voter has one vote, by indicating a ranking of candidates, the voter is
in effect instructing the returning officer what to
do with that vote.
While voters have the option of ranking all candidates on the ballot paper, in practice the average number of preferences indicated is about four.
- from "The 2011 Irish General
Election" by the UK Electoral Reform Society
Credit for diagram below goes to the