Single transferable vote (STV) lets members rank candidates, and fills several seats so that the result reflects the spread of members’ views. To run it online you need a clean electoral roll, a ranked ballot, a count that follows your written election rules, and records you can audit afterwards.

This guide explains how the count works, with a worked example, and then walks through running the election.

How STV works

Voters number the candidates in order of preference: 1 for their favourite, 2 for their next choice, and so on. Each voter has one vote, which moves to their next preference if it is not needed by, or cannot help, their earlier choice. The Electoral Reform Society describes the same three steps: a quota, transfer of surpluses, and elimination of the lowest candidate.

Step 1: work out the quota

Most STV rules use the Droop quota:

quota = (number of valid votes ÷ (seats + 1)), ignoring any fraction, plus 1

This is the formula in rule 47 of the Scottish Local Government Elections Order 2011. The Royal College of Obstetricians and Gynaecologists describes its quota the same way: total valid votes divided by one more than the number to be elected.

Step 2: elect anyone who reaches the quota, and transfer their surplus

A candidate who reaches the quota is elected. Votes above the quota are the surplus, and they pass on to voters’ next preferences.

Under the Scottish rules, every ballot paper in the elected candidate’s pile moves on at a reduced “transfer value”. That value is the surplus divided by the candidate’s total votes, worked to five decimal places (rule 49). Other STV rule sets handle surpluses differently, so your election regulations should say which method you use.

Step 3: if nobody reaches the quota, eliminate the lowest candidate

The candidate with the fewest votes is excluded. Their ballot papers move to each voter’s next preference still in the race. Steps 2 and 3 repeat until all seats are filled.

A worked example

This is an invented example to show the arithmetic. It is not a real election.

A society is electing 2 council members from 4 candidates: A, B, C and D. There are 30 valid ballots:

Number of ballots 1st preference 2nd preference
12 A B
4 A C
5 B –
5 C –
3 D B
1 D C

Quota: 30 ÷ (2 + 1) = 10, plus 1 = 11.

First count: A 16, B 5, C 5, D 4. A has passed the quota and is elected.

Transfer A’s surplus: A has 5 votes more than the quota (16 − 11). The transfer value is 5 ÷ 16 = 0.3125. A’s 12 “A then B” ballots give B 12 × 0.3125 = 3.75 votes. The 4 “A then C” ballots give C 4 × 0.3125 = 1.25 votes.

Candidate First count Transfer from A Total
A 16 −5 11 (elected)
B 5 +3.75 8.75
C 5 +1.25 6.25
D 4 – 4

Exclude D: nobody else has reached 11, so D, with the fewest votes, is excluded. Three of D’s ballots go to B and one goes to C.

Candidate Before Transfer from D Total
B 8.75 +3 11.75 (elected)
C 6.25 +1 7.25

Result: A and B are elected. Many of B’s votes came from A supporters whose first choice did not need them.

STV and Alternative Vote for a single seat

With one seat, the Droop quota is half the valid votes, ignoring any fraction, plus one. In other words, it is a majority. So STV for one seat works the same way as the Alternative Vote (AV). The Electoral Reform Society’s AV page explains it: if more than half of voters put the same candidate first, that candidate wins. If not, the last-placed candidate is removed and their ballots go to next preferences until someone has a majority.

The difference shows with several seats. AV only ever fills one seat at a time. STV fills them all in one count, so a large minority of members can still elect a share of the council.

Your rules may use one name for both. The RCOG, for example, uses STV for its president and vice president elections as well as for council (RCOG STV explainer).

Running the election online

Electoral roll

Fix the date on which membership is checked, and the categories of member who can vote. Export the roll from your membership system and check it for duplicates, lapsed members and missing email addresses or mobile numbers. Keep a copy of the roll exactly as it stood when voting opened.

Nominations

Publish the number of seats, who can stand, and the closing date. Check each nomination against your rules, such as proposers, seconders and consent. Record why any nomination was ruled invalid.

Candidate statements

Give every candidate the same word limit, photo rules and deadline. Publish statements in the same format and a random or alphabetical order. State your rule on ballot order in your regulations, because it can affect results.

The ballot

The ballot should let members rank as many or as few candidates as they like, unless your rules say otherwise. It should block duplicate rankings, show clearly how many seats are being filled, and let voters review their choices before submitting. Send reminders only to members who have not yet voted.

The count

Run the count using the method your regulations set out, including the quota, the surplus method and how ties are broken. Software should produce a stage-by-stage report like the tables above, so anyone can follow each transfer.

Declaration

Publish the result with the quota, first-preference totals, each stage and the turnout. The Royal College of Physicians did this for its 2025 presidential election. It reported that 5,151 votes were cast for president, and gave a 36.3% turnout across its 2025 elections.

Recounts, audit and records

With an electronic count that transfers every ballot at a fractional value, and a tie-break method fixed in advance, the same ballots give the same result every time. A recount then means re-running the count from the stored ballots and checking that the report matches. If your rules allow random tie-breaks, record how each one was drawn.

Good practice includes:

  • writing down in advance who can ask for a recount, by when, and on what grounds;
  • keeping the electoral roll, the anonymised ballot data, the count report and the audit log for the period your regulations or retention policy set;
  • keeping how someone voted separate from who voted, so ballots stay secret;
  • giving an independent scrutineer or returning officer read-only access to the results and audit trail.

Our AGM supports multi-seat STV elections, with stage-by-stage results, audit reports and read-only scrutineer access.

Why royal colleges and professional bodies use STV

Councils of professional bodies often represent members across specialties, regions and career stages. STV lets a sizeable group of members elect someone they support, even if that group is not a majority. Members can also rank candidates freely, without worrying about splitting the vote between similar candidates.

Two public examples:

  • The Royal College of Obstetricians and Gynaecologists states that “STV is the voting system used for electing RCOG Presidents, Vice Presidents and Council members” (RCOG).
  • The Royal College of Physicians says its 2025 presidential election was “conducted using the single transferable vote electoral system”, with independent support from Civica Election Services (RCP).

Whether you must use STV, and which version, depends on your charter, bye-laws or election regulations.

Checklist

  • Confirm in your bye-laws or regulations that STV is permitted, and which quota, surplus method and tie-break rule apply.
  • Set and publish the timetable: roll date, nominations close, statements due, voting opens and closes, declaration.
  • Freeze and keep a copy of the electoral roll.
  • Check nominations against your rules and record any rejections with reasons.
  • Publish candidate statements in a consistent format and a stated order.
  • Test the ballot with a few staff or volunteers before it opens.
  • Send reminders to members who have not voted.
  • Run the count and produce a stage-by-stage report.
  • Let your scrutineer or returning officer review the results before you declare them.
  • Publish the quota, each stage and the turnout.
  • Keep the roll, ballot data, count report and audit log as your regulations require.

Sources

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