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SHE Speaks about…..Voting

By February 3, 2020No Comments

SHE Speaks about voting and the electoral system

When we walk into the polling station on Saturday 8th February we will come face to face with our electoral system in all its glory. Known formally as proportional representation by way of a single transferable vote (or PR-STV for short), it is a sophisticated system that aims to match the seats available to the preference of voters. It gives us choice between political parties, and because there is more than one seat in each constituency we also have choice between candidates from the same party, and we can even disregard parties altogether. This often leads to a long list of candidates on a ballot paper and we are required to rank them in order of preference. In this She Speaks post, we look at mechanisms of how PR-STV actually works, and wonder should we vote the whole way down the paper.


For your vote to be valid you have to write the number 1 (not a tick or an X) beside at least one person on the ballot paper. After that, it is up to yourself. The average voter faced with a ballot paper with 17 names on it usually goes as far as 6 preferences[i]. This means that candidates in a large field really have to work hard at distinguishing themselves to get a preference, never mind elected.

Getting Elected

To get elected a candidate has to reach a magic number called the quota. It is calculated by dividing the total number of valid votes by the number of seats available in the constituency and adding 1 to the answer. When the count starts all the valid votes are thoroughly mixed up, put in parcels of ballot papers according to the first preference on each, and counted. What happens next depends on whether any candidate reaches the quota or not. If a candidate reaches the quota on first preferences, they are deemed elected and any votes over the quota is called a surplus which is distributed among the remaining candidates[ii]. All ballot papers with just a first preference for the elected candidate are taken out of play at this point and the transferable votes are counted by being reorganised into sub-parcels of votes based on the number 2 preference. The remaining candidates get votes from the surplus equal to the percentage of all the transferable votes that name them as the second preference.

Distributing a surplus gets a little trickier to follow the further on the count goes. This is because the ballot papers of each newly elected candidate now consists of their first preference votes and transferred votes. Unlike the surplus that arises on a first count, later in a count the votes that get distributed as a surplus are the actual ballot papers in the parcel of votes that brought the newly elected candidate over the quota. This saves substantially on time and effort. But it distorts the ‘next preference’ logic of PR-STV because it is only the last parcel of physical votes that brought the candidate over the line that determine where the next preference goes, not the next preference of everyone who voted for that candidate[iii]. But it is random though, because the ballot papers are thoroughly mixed up through each other at the very beginning.

If there is no surplus to be distributed, the candidate with the least votes is eliminated. This is simpler to follow because there is no need to calculate percentages or select which physical ballot papers to transfer and count. The eliminated candidate’s votes are just distributed according to the next available preference to the candidates still in the running.

How far should I go down the paper?

The big question. There is no correct answer to this as it is a matter of personal choice. The more numbers you put on your ballot paper the more information you are giving. And that additional information is used to redistribute surpluses of candidates reaching the quota as well as the votes of those eliminated earlier in the count. Anecdotal evidence suggests that people know their top 3 or 4 preferences and also the candidate(s) that they definitely don’t want to get elected. Depending on how strongly they feel about the people they do not wish to see elected they fill in the paper to the end to make absolutely sure that their vote does not inadvertently, transfer by transfer, end up helping their least desired candidate get elected. However if you do not wish a candidate to get in, conventional wisdom is that you leave their name unmarked in case they do inherit your 17th or 18th preference, as unlikely as that might be.


[i] Farrell and Sinnott (2018) ‘The Electoral System’ in Politics in the Republic of Ireland edited by Coakley and Gallagher based on the Irish national election Study data from 2002-2007.

[ii] Gets distributed as the next count if it can elect the highest continuing candidate, or qualify the lowest candidate for recoupment of their election expenses (1/4 of the quota) or lift them above the second lowest continuing candidate.

[iii] Farrell and Sinnott (2018)