Under AV parties can offer more than one candidate without splitting the vote

The Alternative Vote system enables individual parties to put forward more than one candidate and not split the vote.

Under First Past the Post (FPtP) people do not have a second and third preference which, normally not important, matters when there is a lack of proportionality. It (having more than one preference) means that, having given their more desired choice, voters can give their insurance party. Due to this absence people must instead choose their first option as their insurance candidate. Knowing this, parties have no reason to offer more than one candidate, if they do it will split the vote. The Alternative Vote system enables parties to give their supporters at least a choice between perhaps two or more candidates, and not split the vote, which they cannot do under FPtP.

Under an Alternative Vote type system of elections, people do not need to give their first preference to their tactical (least worst) choice. Because of this, a party can field more than one candidate in the knowledge that this will not harm them by splitting the vote, that supporters will give all chosen candidates one of their preferences. A party fielding more than one candidate will not suffer from a split vote if supporters give them each one of their preference votes. Under First Past the Post a political party would not want to field more than one candidate because voters cannot endorse both of them. Being able to endorse more than one candidate means that individual parties are able to offer their supporters more choice, and if they don't voters may come to resent being offered a limited selection of candidates.