PR-STV explainer: How Ireland’s election count system works

Called proportional representation with a single transferable vote, or PR–STV for short, Ireland is only one of one of two countries in Europe, along with Malta, that use this system.

As we saw in the local and European elections, it can lead to days and days of worth of vote counting.

Despite that drawback (or bonus, whichever way you look at it!), PR–STV is considered a fair way of electing politicians, compared to the UK's first-past-the-post or the US's electoral college system.

Here is exactly how the system works:

The vote: It begins with the ballot paper, where voters rank the candidates, putting a number one beside their first preference candidate, a number two beside their second preference, and so on down the line.

Selecting your preference becomes crucial when it comes to counting the vote and choosing who gets elected.

The quota: When all the ballots are cast and polling day is over, then the count begins. The first thing that needs to be calculated is the quota for the constituency.

The quota is the number of votes needed to be elected. Essentially, it is the number candidates need to reach, that guarantees they will not be overtaken.

Once that is calculated, the counting of the votes begins, starting with the first preference votes.

First preference votes If a candidate reaches the quota or surpasses it on this first count, they will be deemed elected.

When a candidate surpasses the quota, their surplus of votes will be distributed to the second preference candidate on each ballot – but not always. It will depend on the size of the surplus.

The surplus must be enough to elect the highest candidate or be enough to either bring the lowest candidate level or higher than the second lowest candidate.

However, if no one reaches the quota on that count, then the candidate with the lowest number of votes is excluded.

From there, their votes are distributed according to the second preference votes, called the second count.

The second count and beyond This is where your preference for candidates is vital, as your ballot continues to be used in the subsequent counts. If you only choose your first preference, then your say will only be taken into account for that first count.

The distribution of votes is also known as transfers, something you will hear a lot when following the election counts.

Candidates are most likely to be 'transfer friendly' to other candidates in their party or to a candidate whose political views are similar.

What we saw in the recent local election was a strong transfer vote between Fianna Fáil and Fine Gael, something to keep a watch for during this general election.

Candidates will continue to be elected or excluded and votes transferred until all the seats in the constituency are filled.

There is, of course, the potential for a recount to be called. This usually happens when a count gets too close and candidates are separated by a small number of votes.

If this happens, there is a repeat of the previous count, with candidates who called for the recount hoping that some mistakes were made, and they gain enough votes to stay in contention.