FAQ on > What is a Preferendum? > Is a preferendum mathematically ok?
Nothing is perfect. Something called Arrow’s ‘Impossibility Theorem’ is a complicated piece of mathematics which proves that there is no such thing as a perfect voting system, something which, no matter what the preferences of the voters, will always give “the will of the people”.
Of those voting systems which are good, the mbc and Condorcet are the best, and not least because they are the only systems which take account of all the preferences cast
The mbc (preferendum) is not proportional, which is why, in an election, it is better to use qbs or a matrix vote. Also, the preferendum suffers from something called the irrelevant alternative. In a five option poll on options A, B, C, D and E, option C might be the most popular. But if the same people voted with exactly the same preferences on a four-option ballot of options A, B, C, and D, then maybe B could be the most popular. This is why it is very important to have a specific procedure for choosing the options, as above in answer No 3.Last updated on September 19, 2008 by Deborda