Australian Politics and Policy - Senior, 2019a

Electoral systems
linedupandfilledinandcastaballot,justforitnottohavemattered.Suchvotesare
called ‘wasted votes’ in the political science literature; we regularly assess electoral
systems on the basis of the percentage of wasted votes.
The Australian House of Representatives uses preferential voting, a less common
majoritarian electoral system. 12 In a preferential system, voters mark their preferred
candidate but also get to rank the other candidates. Voters’ ability to rank candidates
in order can be seen as offering an alternative: if my favourite candidate (John Scott)
is not popular, then I want my vote to go to my next preferred candidate (Jessica
Shaw), and so on.
When voting closes at the end of election day, electoral staff count up all of
the ‘1’ (i.e. first preference) votes. You might imagine a pile of ballot papers for
each candidate, based on how many voters gave the candidate their number ‘1’
vote. Once this count is finalised, the candidate who received the fewest ‘1’ votes
is eliminated, and their votes redistributed to whichever candidates received the
number ‘2’ votes on these ballot paper. This continues until there are only two
candidates left; you might have heard of ‘two-party preferred’ or ‘two-candidate
preferred’ results – this is exactly that. After unpopular candidates are eliminated
and voters’ preferences distributed, the final two candidates are the ‘two candidates
preferred’.
Preferential voting has one distinct advantage over plurality voting, and one
distinct disadvantage. The advantage is that very few votes are wasted; even if a
votercastsavotefortheleastpopularcandidateinanyelection,theirvotewill
transfer to their next favourite candidate, and their next favourite candidate, and
so on. Inevitably, this means that any election comes down to the two candidates
whom voters are least likely to rank last, rather than the candidates they are most
likely to rank first. However, this is quite a complicated electoral system (requiring
voters to place a sequential number next to every candidate or else invalidate
their ballot), which disadvantages voters from non-English-speaking backgrounds
and those with low literacy. This trade-off is an ongoing challenge for electoral
administrators.
In majoritarian systems – whether plurality or preferential – candidates (or
parties) who are ideologically similar usually try to avoid ‘stealing’ votes away
from each other. Imagine, for instance, two socialist-leaning parties nominating
candidates in an American congressional district. If they do not co-ordinate, they
mighteachwin26percentofthevote,leavingaconservativecandidatetowin
with 48 per cent of the vote. For both socialist-leaning candidates, this is the least
optimal outcome – they lose, and a conservative (i.e. the most ideologically distant)
candidate wins.
12 ‘Preferential voting’ is the commonly used term, while academics and researchers tend to describe
this system as ‘alternative voting’, ‘ranked choice voting’ or ‘instant run-off voting’. These terms all
describe the same system.
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