You don’t have to be a prize-winning mathematician to understand AV… but it helps

According to the Yes campaign, AV is a ‘simple change’ and as ‘easy as 1, 2, 3’.  Unfortunately, members of the American Mathematical Society found that it was too complicated for the election of their own officers – and chose to abandon it in 1990.

The American Mathematical Society was founded in 1888 to further the interests of mathematical research and scholarship. Their primary aim is for the society to improve the quality of mathematics teaching in the US.

The Society began to turn away from AV after Professor Steven Brams of New York University wrote an article that highlighted the flaws of AV, and pointed out that the Society’s ballot papers offered factually inaccurate advice to voters

The ballot papers had said: ‘It is advisable to mark candidates in the order of your preferences until you are indifferent concerning candidates whom you have not ranked’. Under AV, however, voters can play the system by marking candidates in a different order or by ‘truncating’ preferences (e.g., only putting a first choice, with no second choice). This is because the Alternative Vote System is what mathematicians call a ‘non-monotonic’ electoral system.

The Society found that the ballot counting was too complicated and time-consuming. According to Professor Brams, the Society ‘found it too burdensome to tally ballots under the AV system' because they were hand-counting the ballots. 

The Society therefore switched to another voting system - a modification of the UK's current ‘First Past the Post’ system.