Secondary Preference

In preferential or ranked-choice voting systems, a secondary preference is any choice a voter ranks below their first preference (the second, third, fourth, and so on). These rankings only become relevant when the voter's higher-ranked candidate cannot benefit from the vote — typically because that candidate has been eliminated for having the fewest votes, or, in proportional systems, has already met the quota required for election.

Secondary preferences are the mechanism that makes ranked systems function. Under instant-runoff voting (IRV), used for Australian House of Representatives elections and for U.S. contests including Maine's federal elections (since 2018) and New York City's mayoral primaries (since 2021), the lowest-polling candidate is eliminated each round and their ballots are redistributed according to the next available preference. Under the single transferable vote (STV), used in Irish Dáil elections and Australian Senate contests, surplus votes from candidates who exceed the quota are also transferred down the preference order, often at a fractional value.

Secondary preferences shape strategy and outcomes in important ways:

• They reduce the spoiler effect, since voters can rank a minor-party candidate first without "wasting" their vote.
• They reward candidates with broad appeal, because winning often requires being many voters' acceptable second choice, not just a polarising first choice.
• They can produce come-from-behind winners, as occurred in the 2018 Maine 2nd Congressional District race, where Jared Golden trailed Bruce Poliquin on first preferences but won after transfers.

Parties in preferential systems frequently issue how-to-vote cards recommending preference orders, and inter-party preference deals — long a feature of Australian politics — can determine who ultimately wins a seat. Critics argue that lower preferences are weighted equally with first preferences once activated, which they see as distorting voter intent; defenders counter that secondary preferences capture a fuller picture of consent than a single-mark ballot.