How Accurate Was The Same-Sex Marriage Polling?

The abrogation of responsibility and waste of resources that was the Marriage Law Postal Survey has now concluded with a Yes vote of 61.6%, based on a very high turnout of 79.5%.  Every Australian poll on same-sex marriage in the last ten years has shown more voters supporting same-sex marriage than opposed, with the exception of a single fledgling ReachTEL in 2011, so this has been seen initially as another good result for Australian polls.  In contrast, non-polling "big-data" approaches based on social media analytics failed completely, with the EqualityPulse site mostly favouring the No vote until after the polls had closed and a Griffith University study bombing embarrassingly.  (Be wary of anyone who claims their methods predicted Trump would win - most who predicted him to win did so because they wrongly expected him to win the popular vote.)

This is being taken as another strong result for Australian polling, but the reality is not so snazzy, and more consistent with experience elsewhere.  Below are all the final poll results by each pollster that I could find.  (Some pollsters conducted several polls, typically finding little variation through the survey period.) The polls vary in methods - some asked about results based on those who had voted, some asked about the votes of those who intended to vote and some just asked a basic question about support or opposition to same-sex marriage.  One (Ipsos) appears to have asked about voting intention among those certain to vote only.  In many cases, inadequate public documentation means that it is not entirely clear what the pollster did.

Marriage Law Survey Turnout Is High ... But Not That High!

(This article is being progressively updated through the survey - KB)

The first release of turnout estimates from the Australian Bureau of Statistics for the same-sex marriage postal survey has created some interest.  The ABS estimates that as of Friday 29 September, 9.2 million survey forms have already been received, 57.5% of all enrolled voters.

The ABS notes that this is an estimate only.  It may not represent the received yes/no vote as not every single one of the forms submitted will be valid (some small percentage may be posted back deliberately blank, for instance, or even with both boxes ticked.)  It is also unclear to me whether this estimate is based in some sense on a count of forms or on a count of envelopes, since there could well have been some cases of multiple forms being posted back in the same envelope, or of empty envelopes being posted (heck, I used to do this to junk-mailers who included a reply-paid all the time).  It also doesn't include anything that has been posted but was still on its way to ABS as of Friday.  So the figure is likely to be at least a few percent short of the number who have now voted.

Recent Polling On The Same-Sex Marriage Postal Survey

The national ABS postal "survey" on whether the law should be changed to allow same-sex marriage in Australia is now in its second week.  A number of pieces of polling have been published or alluded to since my last general polling update, but what do they really tell us about the outcome and how reliable are they?  At this stage there is still much that we do not know.  It is too early to be certain Yes has it in the bag, but the widespread narrative that support for Yes is crashing rapidly and that this is another Trump or Brexit coming is so far not that well supported by the evidence.

Public Polling: Ipsos

Firstly, the public polling.  Last week saw an Ipsos poll which buoyed some worried Yes supporters with a 70-26 Yes response, one of the highest Yes votes ever recorded in a poll in Australia.  Indeed, as far as I'm aware, this score has only been exceeded in a few commissioned polls and one Morgan-SMS (a suspect polling method) which did not use an undecided option.  The Ipsos also found a 70% Yes response among the 65% of voters who rated themselves as certain to vote, and found a gender gap with 72% of women and 59% of men saying they were certain to vote.

Poll Roundup: Newspoll Moves! It Is Alive! (includes same-sex marriage polling)

2PP: 53.5 to Labor (+0.3 since last week)
Labor would win an election "held now" with a large majority

Time for another roundup of the state of play in federal polling.  This week's exciting development was that Newspoll, after a record six consecutive 2PPs of 53-47 to Labor, finally moved by a whole point to 54-46!  I am especially excited by this because had this week's result been another 53-47, I was going to lead off with a mock Death Certificate, and now I do not have to.

This briefly took my aggregate to an equal term high 53.8 to ALP (I tweeted this as 53.9 but later found a very small error) but then Essential moved back a point the other way after two 54s, and the primaries in YouGov didn't do a lot, so I currently have it at 53.5 to ALP. That was the Coalition's winning lead in the 2013 election, and also just shy of what Labor had when Tony Abbott was removed.  

The strange 2PP results of YouGov continue to baffle - this week it has the Coalition with a 51-49 lead off primaries that would normally imply something like 53.1% to Labor.  I discussed this issue last time, and the average difference between YouGov's 2PPs and the last-election 2PPs for their primaries is now running at a massive 2.9 points.  As noted last time, it's possible that the current last-election 2PPs are overstating Labor's lead, especially because of One Nation issues, but it's highly unlikely that they're doing so by three points.  Much more detail on the YouGov mystery from William Bowe here.

All Polling On The Plebiscite Has Problems

In the last few weeks we've seen some new polling results concerning the Coalition's proposed plebiscite on legalising same-sex marriage (or as it is more accurately described, marriage equality).  It is extremely well-established in polling that a clear majority of voters support legalising same-sex marriage, but whether voters support deciding the matter by plebiscite or parliamentary vote has been less obvious.  The very inconsistent results from various polls on this subject are causing a fair degree of interest and confusion.

In this article I suggest that the range of results we are seeing on the question of a plebiscite vs a parliamentary vote is largely a result of differences in design between different polls.  Which poll is right and which poll is wrong?  My view is that all of them are suspect.   The question is a difficult one to poll and none of the polls offered thus far have even got close to a design that accurately reflects the choices the parliament, voters and activists face.

Postal Plebiscite: Australia's Biggest Bad Elector Survey

(Note added Aug 2017: This article from April has received much interest lately.  For new comments go to Electoral Process, But Not As We Know It: Postal Plebiscite V2).

The federal Coalition went to the 2016 federal election with a commitment to hold a national non-binding plebiscite on marriage equality (aka "same-sex marriage") prior to any further parliamentary vote on the issue.  The plebiscite was, as noted here before, a bad idea in policy terms, though it was mostly successful in neutralising marriage equality as a campaign issue.  The plebiscite plan was voted down in the Senate, leaving the whole issue apparently unable to progress within this term.

The option of simply changing the law seems impossible because religious reactionaries within and supporting the Coalition won't allow it.  (They're the ones who don't understand why people keep talking about marriage equality, but would bring down the Prime Minister and/or destroy their own party even in a failed attempt to stop it.) Leaving the issue as a festering distraction til the next election isn't too attractive either, so along comes Peter Dutton with a proposal to have the plebiscite anyway, but to do it by post.  Voting would be optional.

The idea of holding a voluntary ballot that does not need the approval of parliament is not new; this option of a "fee-for-service" ballot under Section 7A of the Electoral Act was discussed in the Senate plebiscite report. The option was not costed at the time because there was no proposed legislation to implement it.