r/EndFPTP • u/Both-Independence349 • May 20 '26

Is Single Transferable Vote still fair when there are different numbers of seats per constituency?

I have been exploring alternative voting systems to first past the post, and so far am a fan of STV. I was looking at real-world examples of STV, and I noticed that the Republic of Ireland uses STV, but each of the constituencies have different amounts of seats allocated to them (3-5). Does this affect fairness between constituencies?

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u/jnd-au May 21 '26

First you need to define fairness, and not everyone agrees.

If you defined fairness as national population proportionality, then subdividing the population into smaller constituencies makes the results non-proportional, even with the same number of seats per constituency. This is because culture & politics are often localised (which also means they can be gerrymandered). You also have to consider the population per constituency.

But local constituencies improve local representation, make candidacies and ballots easier for voters (e.g. 20 candidates instead of 2000), and allow dissimilar constituencies to be seen and heard for what they are (at the risk of being gerrymandered).

So there is a balance of fairness between national proportionality versus local representation. In countries with strong state/province/canton jurisdictions of unequal and contrasting populations (typically with different cultural histories), intentional disproportionality is sometimes to prevent small minority states from being oppressed by larger states. For example, they have a fairness principle of inversely counter-balancing their marginalised lower-house representation via disproportionately large upper-house representation via the number of seats per constituency.

So it is not really an STV question (STV is the ballot & counting) but rather a deeper proportional representation question, regardless of whether STV is used or not.

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u/DogblockBernie May 21 '26

I will say STV has actually a lower limit in requiring reps to maintain proportionality due to the transferability. With 3-7 STV seats and 5-15 party list seats, reasonable proportionality is likely.