Oh Yes We Do Have Strategic Voting In Australia (Sometimes)

On Wednesday Alex Turnbull, who has been campaigning for voters to evict the Liberal Party from his father's former seat of Wentworth, switched his support from Labor to independent Kerryn Phelps on strategic grounds.  Amusingly, Turnbull jnr justified his support by reference to a popular American text called "Gaming the Vote" by William Poundstone, and posted a colourful excerpt explaining how the squeezing out of a centrist candidate who finishes in third places can lead to "unpalatable, Wizard-or-Lizard dilemmas".  After Clinton-vs-Trump, or even the utter farce that has been the present term of Australian parliament, wizards and lizards are both sounding pretty good at the moment.

The idea here is very simple: if Kerryn Phelps makes the final two she is more likely to beat Dave Sharma (Lib) on preferences from Labor (which will include some votes originally for the Greens and minor candidates), than Tim Murray (Labor) is to beat Sharma on Phelps' preferences should he make the final two.  Phelps is (mostly) seen as the more centrist candidate in an electorate that has never elected a Labor MP.  There will be voters who want to send a protest vote against the Liberals for disposing of that other Turnbull or whatever other reason, but who cannot bring themselves to vote Labor.



And yet, I have seen a few politically active people on Twitter claim (and persist in claiming after being refuted) that strategic voting is a non-issue in a preferential system, that we don't ever have it in this country and never need to, and that all a voter need ever do is put the candidates in order of preference and the system will process that as best for that voter as it can.

Now, normally it doesn't bother me if people who seem to be smart enough to know better insist on damaging their own voting power.  Also I have no interest in promoting a Phelps vote myself and I'm not sure I'd put her above either major party's candidate if I had the fortune to be a Wentworth voter.  But above all else, this goes to the question of our electoral system, what it is good for, what are its strengths and weaknesses, is it prone to gaming, and does it sometimes leave voters with difficult strategic choices that they do not have the information needed to make.  These questions need answers and the fact is that an incentive for strategic voting is a real, if rare, thing in our House of Reps system.

Here are some examples of strategic voting scenarios in Australian single-seat elections with preferencing (either compulsory or optional, the same points apply in each case).  The extent to which strategic voting actually occurred in each case is not that relevant; the point is that there was clear room for using it if voters were concerned with a specific outcome.

* In the 2009 Frome by-election in South Australia, independent Geoff Brock won after coming third on primaries.  After the preferences of minor candidates Brock reached the top two by a whisker (30 votes).  80% of Labor's preferences flowed to Brock and he won by 665 votes.  But had Brock been excluded, only 68% of his preferences would have flowed to Labor, and Labor would have lost by 643 votes.  Therefore, if someone's sole concern was beating the Liberals, their best strategic vote was to put Brock ahead of Labor and the Liberals last.  Those who voted Labor-Brock-Liberal actually nearly caused the Liberals to win, and indeed had 31 Liberal voters voted 1 Labor, the Liberals would have won the seat with Brock eliminated.

* In Denison in 2010, Andrew Wilkie also won from third.  After he narrowly held off the Greens for third place, Wilkie received a flood of Greens preferences and jumped the Liberals to easily make the final two.  He was then narrowly elected over Labor on Liberal preferences.  But had the Liberals made the final two, Wilkie's preferences would have elected Labor with a large margin.  The Liberals always knew they would never win Denison so it made strategic sense for Liberal voters wanting to kick Labor out of the seat to vote for Wilkie ahead of their own party.  And quite a few probably did.

* In the recent Wagga Wagga by-election there was a close three-way split between independent Joe McGirr, the Liberals' Julia Ham and Country Labor's Dan Hayes.  Hayes was eliminated in third and his preferences flowed massively to McGirr who scored an enormous win with nearly 60% two-party preferred.  Had McGirr been eliminated at this stage (which he avoided by 3.4%), Hayes would still have won on his preferences, but it would have been extremely close (just 106 votes in it).  So for those who only wanted to beat the Liberals, McGirr was easily the safer strategic vote, while a vote for Hayes was a much bigger risk.

* In the seat of Rockhampton in Queensland 2017, the ex-Labor independent Margaret Strelow was second on primary votes and appeared likely to win the seat from Labor on LNP and One Nation preferences.  But there was a problem - Strelow didn't stay second.  Preferences from the LNP candidate in fourth put One Nation into second and Strelow was eliminated, with her preferences causing Labor to win the seat.  Had just 372 of 3076 voters whose voted flowed from LNP to One Nation instead strategically preferenced Strelow, Strelow would have made the final two and beaten Labor.  Instead, these LNP-One Nation voters, many of them following the LNP card, caused Labor to win the seat moving Labor one more seat away from the embarrassment of minority government.  Admittedly for a conservative voter there was probably little to choose between Labor and Strelow, but such gifts to endorsed Labor candidates made the LNP's attempt to blame One Nation for Labor's majority hypocritical (not to mention factually wrong).

Of course, the vast majority of seats are not like this.  In nearly all seats everyone knows who the final two will be and it is only how the voter orders those two that makes a difference (except for public funding).  There are also other cases, like the three-cornered seat of Prahran (Vic) 2014, where strategic voting could have made a difference, but there was no way to predict how to do it (whether Greens votes will flow more strongly to Labor than vice-versa varies a lot between seats).  However, the case of Wentworth is the stock-standard case in which strategic voting is an issue: the two major parties against a prominent independent who is likely to be preferred by each party's support base over the other.

In any such case, if someone's sole concern is beating one of the major parties, then the correct strategic move is to preference the indie above both major parties, putting the party they want to lose last.  If the indie ends up being uncompetitive, it doesn't matter anyway as their preference flows to the preferred major party at full value.

It's not so simple for a voter in this position: They would ideally like Labor to win the seat. Phelps is their second preference and they definitely don't want Sharma to win.  This one, as with the choice facing Labor supporters in Wagga Wagga, is a tricky case of how the voter might balance risk and reward.  Is it worth voting for Murray and increasing his chance of winning when by doing so you also increase the chance of Sharma winning?  Or is it better to play safe, sacrificing Murray's chances in order to reduce Sharma's?

Ideally, to make this decision, the voter would like to have answers to these questions: If Phelps makes the top two, how likely is she to beat Sharma?  If Murray makes the top two, how likely is he to beat Sharma?  If the answers are, say, 80% and 50%, but you think a Murray win would be four times as good as a Phelps win, you might well still preference Murray over Phelps.  However, polling is nowhere near accurate enough to answer the probability questions.

As it happens only two of the ten (!) Wentworth seat polls have looked at this question.  The Refugee Council ReachTEL found Phelps winning 53-47 if in the final two but Murray scoring 50-50 if he's in the final two. The Voter Choice opt-in experimental poll actually found Murray winning by a slightly larger margin than Phelps (55.6 vs 55.4) but that should be treated with extra caution as it is contrary to the past history of these things and to Phelps' history of all-over-the-place political positioning.  Both results would be based on trivially small sample sizes.  If the first poll is accurate then the risk difference in voting for the two candidates is large.  But if there has been a swing away from Sharma to both opponents since the poll was taken, the risk difference reduces.  The problem is that seat polling in Australia is such a load of rubbish that if the polls say Labor is marginally ahead or marginally behind the Liberals on a 2PP basis, that might be completely wrong.

There is also a strategic voting issue for Liberals (see the Frome discussion above).  If they believe they are definitely going to lose to Phelps should Phelps be their opponent, then a small number of them may as well vote 1 Murray and attempt to knock Phelps out.  But in doing so (especially if too many do it) they increase the risk that if Murray does make the final two, he wins (which is an even worse result for the party, except that it increases their chance of winning the seat back at the election.)

Strategic voting scenarios are common in our various Upper House systems too, though that is beside the point of the current article and has been explored elsewhere on this site (see "tactical voting" section).

How could this be fixed?

The incentive to vote strategically in this way (in these rare cases) could be removed if Australia used one of many possible Condorcet systems.  In a Condorcet system, if a candidate is preferred by the voters head-to-head over every other candidate, then that candidate (in this case potentially Phelps) always wins. In such systems, there will always be a pairwise comparison between Phelps and Sharma, so there is no reason for someone who prefers Murray over the others to put Phelps ahead of Murray.

However,  Condorcet systems have practical drawbacks.  At least one candidate has to be compared pairwise against every other candidate to find the winner, so in practice I'd expect full data entry of all ballots (as in NSW) to be required.  Secondly in rare cases there isn't a Condorcet winner, so some form of consensus would have to be reached on the most appropriate tie-breaking method (and what risks that created of strategic voting too).  Discussion of this tends to quickly reach a level of nerdiness that the average voter has no hope of following.

There are very few cases based on actual vote data where the Condorcet winner would have been different to the person who actually won (Rockhampton mentioned above is probably one). My perception is that the Condorcet winners have a very high strike rate in these three and four candidate contests.  But what impact a Condorcet system would have on voting over time is hard to predict.  If it led to more focus on intermediate candidates and further eroded the primary vote of major parties, it might lead to a system where several candidates were competitive for certain seats.  That sounds great but I am just a little wary of the potential for it to unlock the door to how-to-vote-card preference trading, a scourge we just (largely) got rid of from our Senate system.

Anyway, as the strategic voting issue is a rare novelty in Australia, rather than a frequent necessity as in first-past-the-post systems like the UK's, I doubt there will be a serious push for change on this front any time soon.

"But Strategic Voting Is Wrong"!

There is a view in some circles that one should never advocate strategic voting and one should always put the candidates solely in one's preferred order and let the system sort out the mess.  Here I take no view on the morality of strategic voting - it is up to any voter to decide whether they wish to do it or not.  However it is simply a fact that our system has some weakenesses and that it is sometimes possible, in rare cases, to cause the candidate you least want to win to succeed by voting 1 for the candidate you most want to win.  I think that knowledge that this can be the case should be out there, and people can make their own decisions on what they do about it.  I only wish the polling data had the quality needed to provide better information about the risks in given cases!