The South Australian government announced earlier this week that they plan to introduce legislation that will change the voting system from compulsory preferential voting (CPV) to optional preferential voting (OPV).
There are principled arguments for such a change, as it would likely ensure more votes are counted and the informal rate drops, but it is also something which would likely help the Liberal Party in the short term against Labor – although OPV has sometimes benefited Labor over the Coalition in the past.
The current system requires voters to number every box on their ballot paper (although savings provisions do allow some votes to be counted if the voter doesn’t number every box). CPV is used to elect the House of Representatives and lower houses in Queensland, Victoria, Western Australia, South Australia and the Northern Territory.
Optional preferential voting would mean that votes would be counted as long as there was a single ‘1’, even if there were no further preferences. Voters would still be able to mark preferences, but they would not be necessary for their vote to count. OPV is used to elect the New South Wales lower house, and has been used until recently in Queensland and the Northern Territory.
There are principled arguments in favour of OPV, but you can’t look past the political self-interest that motivates the Liberals to propose this change.
Under OPV, preferences are less likely to flow, and this tends to favour the candidate who is leading on primary votes. It’s harder to overtake a leading candidate when some preferences exhaust, and reduce the pool of preferences.
Labor tends to do better under CPV, primarily because of Greens preferences. Most Greens preferences flow to Labor when they are required to mark preferences, but a lot of Greens voters instead choose to exhaust when that’s an option.
Antony Green also points out that, in the South Australian context, compulsory preferences have helped independents win seats off the Liberals, usually with the benefit of Labor preferences. Of the 26 contests in South Australia since 1982 where a candidate trailing on primary votes went on to win, 14 were won by Labor, 11 were won by independents or minor parties, and just one was won by the Liberal Party. A number of those independents went on to support minority Labor governments after the 2002 and 2014 elections.
There is nothing permanent or unchanging about OPV benefiting the Liberal Party. Party systems change over time. Labor once supported OPV in an era when Democratic Labor Party preferences benefited the Coalition. The Whitlam government attempted a switch to OPV, and the Wran Labor government introduced OPV in New South Wales in 1980.
After OPV was implemented in Queensland in 1992, the system proved very helpful to Labor at the 1998 election, when the conservative vote split badly between the Nationals, the Liberal Party and One Nation. OPV was seen as being particularly difficult where the Nationals and Liberals ran against each other, but the NSW Coalition solved that problem by pretty much eradicated “three cornered contests”.
Queensland Labor changed the voting system back from OPV to CPV after the 2015 election, just in time for One Nation to re-emerge and make CPV seem much less advantageous for Labor than might have been thought.
Still, we can generally assume that as long as the Greens are the biggest minor party, and independents are a stronger presence in conservative seats, that Labor will benefit from CPV and the Coalition will benefit from OPV.
But let’s put aside the partisan advantage: what are the arguments for OPV?
The compulsory preferential system tends to produce a lot of informal voting – about half of all informal votes are attempts at casting a vote, but don’t meet the strict requirements of consecutive numbering of most or all boxes on the ballot paper.
Casting a formal vote becomes harder as more candidates are added to the ballot, leading to higher informal rates when lots of candidates run. Informal voting also tends to be higher where there are more voters who speak languages other than English. Incidentally, Labor tends to believe they would benefit if these votes were counted as formal, but the evidence is not clear.
On the contrary, CPV maximises the number of votes which contribute to the final outcome of the race, when the race dwindles down to two candidates. Under OPV it’s possible for candidates to win with substantially less than 50% of the total vote. Yet many of the votes rendered informal by CPV’s strict formality rules wouldn’t actually exhaust – votes for Labor and Liberal in most seats are never at risk of exhausting, yet those voters can’t simply just cast a ‘1’ preference.
In theory, there is nothing stopping voters choosing to indicate preferences under an OPV system, but it does create space for parties to encourage ‘just vote 1’ campaigns when they don’t expect to benefit from preference flows.
So you end up with a dilemma: do you ensure maximum numbers of votes are formal, or do you use a strict rule to force more of those voters to number enough preferences to prevent their vote exhausting?
I personally come down on the side of OPV on principle – I don’t think you can justify rendering votes informal when someone has indicated a clear preference.
But that doesn’t mean we should have a system which treats a simple ‘just vote 1’ as a default.
I think we’ve seen a way forward in the Senate reforms introduced prior to the 2016 election. The instructions on the ballot paper (repeated by AEC staff and advertising) tell voters to vote 1 to 6 above the line or 1 to 12 below the line, but the threshold for formality is lower: just 1 above the line or 1 to 6 below the line.
This was backed up with a strong advertising push in 2016: the AEC took an active position in support of preferences (although this wasn’t perfect – in many cases this advice was seen as telling voters to number 6 boxes, instead of numbering at least 6 boxes).
I think such an approach could also work for a single-member lower house election. I would think you would give official advice to voters to number multiple preferences (maybe “at least 5” is enough – if there’s 20 candidates I don’t think there’s any sense in telling voters to number every box).
But you would need a solution to the ‘just vote 1’ campaign problem. Such a campaign doesn’t work in a Senate election, where all parties can benefit from preferences. The likely beneficiary of preferences is much easier to predict in a single-member election, and thus there’s an incentive for the other side to try to undermine preference flows. Perhaps we just need a rule requiring campaigns to recommend at least as many preferences as the official advice.
Some work needs to be done, but I think it should be possible to encourage high rates of preferencing without throwing out perfectly good votes.