How to vote
We use a system called Single Transferable Vote to count all elections. The definitive guide to the system as we implement it is How to conduct an election by the Single Transferable Vote, 3rd Ed, published by the Electoral Reform Society (1997). This is freely available online. The text of the below explanation also leans heavily on the Electoral Reform Society.
For an easy to watch explainer of the principles of STV, take a look at this (very sweet) video explaining the system in the context of elections in the Republic of Ireland, which are held using the same system.
STV Counts
STV for elections in which there are multiple places to be won is a form of proportional representation, where the outcome divides places in proportion to the preferences of voters. The same methodology can also be applied to elections with a single place to be won, where it is generally called the Alternative Vote system.
Voters rank their preferences on the ballot between the candidates and RON (see below). They can rank as many or as few candidates as they like.
To get elected, a candidate needs a set amount of votes, known as the quota. The system counting the votes works out the quota based on the number of vacancies and the number of votes cast.
Each voter has one vote. Once the counting has finished, any candidate who has more first preference votes than the quota is elected. But, rather than ignore extra or surplus votes a candidate received after the amount they need to win, these votes move to each voter’s second preference candidate.
If no one reaches the quota, then the least popular candidate is removed. People who voted for them have their votes moved to their second favourite candidate. This process continues until every vacancy is filled.
Re-Open Nominations (RON)
There is also an additional candidate on the ballot in every election the SU runs – Re-Open Nominations. If Re-Open Nominations is elected, no more candidates are elected. Nominations for any remaining places are then re-opened, and the election is run again.
Election Safeguards
Cambride SU elections are overseen by the Returning Officer and Deputy Returning Officer (RO & DRO). These two external roles ensure that Cambridge SU run fair and equal elections, plus adjudicate on election rules & rulings, and oversee election counts. There are also two elected students who oversee the counts.