What is PR-STV?
Imagine your first-choice candidate is eliminated: the next continuing preference you marked may receive your vote, which is why a numbered ranking can matter beyond the first count.
| Your next preference is used when… | Example | |
|---|---|---|
| Your candidate is elected with a surplus | There are more votes than needed for the seat. | Your ballot may transfer at a fraction of its value to your next continuing choice. |
| Your candidate is excluded | They have too few votes to stay in the count. | Your ballot can transfer at its current value to your next continuing choice. |
| You stop ranking | No continuing preference remains on your ballot. | The vote becomes non-transferable at that point. |
On the course: CSPE strand 3 and Leaving Cert Politics and Society topic 2 both ask how the Dáil is elected. The answer is PR-STV, and the exam wants the quota plus a transfer, not only the name of the system.
Unlike a single-X ballot, PR-STV lets you choose between people, not just parties. In a five-seat constituency, voters can help elect several TDs from different parties in one election. The 34th Dáil, elected on 29 November 2024, was filled this way: 174 seats across 43 constituencies, with transfers deciding seats that first preferences alone did not.
The system is set out in Irish electoral law and explained in plain language by An Coimisiún Toghcháin.
Step-by-step: how a count works
1. The quota (Droop formula): Quota = (Total valid votes ÷ (Seats + 1)) + 1, ignoring fractions. In a three-seat constituency with 60,000 valid votes, the quota is 15,001.
2. First preferences: Ballot papers are sorted by who got each voter's number 1. Anyone at or above the quota is elected immediately.
3. Surplus transfer: If an elected candidate has more votes than the quota, the extra votes transfer to next preferences on those ballot papers, usually at a reduced value proportional to the surplus.
4. Elimination: If no one new reaches the quota, the candidate with the fewest votes is eliminated and their votes transfer to the next available preference.
The process repeats until all seats are filled. The last seat can go to a candidate below the quota if everyone else is elected or eliminated.
A classroom count, not a real constituency: 100 valid votes, 2 seats. The quota is 34, because 100 divided by 3 is 33, the fraction is dropped, and you add 1. A has 40 first preferences, B has 35, C has 25. A is elected with a surplus of 6. Suppose 30 of A's 40 papers have B next and 10 have C next. Each of A's papers transfers at 6/40, which is 0.15. B receives 4.5 and reaches 39.5, so B is elected. C receives 1.5 and stays on 26.5. That is the Gregory method in miniature. Real counts use the same idea on tens of thousands of papers.
Why voting down the ballot matters
If you only mark a number 1 and stop, your vote dies when that candidate is eliminated or when all your higher choices are settled. Ranking 2, 3, 4 and beyond gives the returning officer somewhere to send your vote later in the count.
This is why parties ask for transfers, and why Independent TDs can win from lower starting positions when larger candidates are elected or eliminated.
After the count: follow your TD
Once TDs are elected, DáilDex monitors their votes, speeches, and parliamentary questions from the official Oireachtas record.