A Condorcet count suffers from something called a paradox: if Ireland beats Scotland, Scotland beats England, and England beats Ireland, (as in the 2008 six-nations rugby internationals), no-one will know which team is the best. (Except the Welsh.)
Similarly, if in a 3-option ballot, 43% have preferences A-B-C, 33% have B-C-A and 23% C-A-B, then a majority (of 66%) prefer A to B, a majority (of 76%) prefer B to C and a majority (of 56%) prefer C to A. So A is more popular than B is more popular than C is more popular than A is more popular than… ad infinitum. This is called the paradox of voting.A Condorcet count suffers from the paradox but not an irrelevant alternative. An mbc suffers from an irrelevant alternative but not a paradox. So, to be really sure, as in a parliament, it is better to conduct the count according to the rules of both an mbc and Condorcet; and if the winner in both is the same, then you can be 99% sure you’ve got the right answer.
Last updated on September 19, 2008 by Deborda