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.



This figure has attracted attention because of discrepancies with turnout figures in some of the polling.  Some early turnout estimates and projections were reported in a previous roundup, but we're now at the stage where almost everyone got their survey over a week ago.  Yes campaign internal polls have reported up to 77% of enrolled voters voting.  A Sky ReachTEL with a massive sample size reported 79% having already voted.  This contradicted a separate, unsourced ReachTEL with a smaller but still decent (1000) sample size that found 72% saying they had voted or definitely would vote, including c. 60.5% who had already voted.  (That other ReachTEL also had a much more normal Yes vote for this pollster - 61%).

If the Sky ReachTEL is to be believed as reported, then the postal vote is already over as a contest, with a massive 64% of enrolled voters already voting Yes, with Yes running at 80.5% among those who've already voted, and projected to finish at 76.8% including those who say they will vote.  That would be the second-highest Yes vote on a two-answer basis in any poll in the country on the issue.  If the other ReachTEL is closer to the mark then No is still mathematically in it if it can get some of those who aren't sure they will vote to do so - but even then it would need a very large majority of the remaining votes.

There aren't any polls yet that are giving No a sniff of actually winning, but even assuming Yes does win comfortably, the final turnout and the magnitude of the result are likely to be significant in terms of the pressure on government for a quick solution following the vote.  Especially, should there be more Yes votes than No votes, the condition for allowing a bill will have been activated and a bill of some sort should then pass. But if the total number of Yes votes is less than half all the enrolled voters, some mendacious goalpost-shifting MPs may seek to argue that that's not good enough and use this as an argument for voting against same-sex marriage or mucking about to attempt to delay legislation.  Or someone might say that, say, 66% is not enough, it should be 70%.  If you think nobody could possibly be that stupid, I've heard there was a lengthy discussion of this concept on Sky!

The higher the turnout, the higher the chance of the Yes vote exceeding one in every two enrolled voters and making things really clearcut for even the most evasive pollies, but the chances of this happening are unclear given the widely divergent turnout figures we are seeing.

So who is right and who is wrong?  The ABS count is bound to be a few points short of the current turnout, but the accuracy issues with its estimates shouldn't be enough to explain gaps of twenty points.  I think that some of the polls have turnout a little too high, and that the most likely reason for this is that they are undersampling politically apathetic voters, who will tend not to respond to this survey at all.  These voters might either not be opting into polling in the first place, or might be part of online panels but rarely online.

Anyway, we have at least another five of these updates for pollsters to calibrate their estimates against!

The SkyNews ReachTEL is so strong for the Yes vote that I am treating it with caution pending at least the release of full details of the poll.  It's very disappointing that for a poll of such a size we have not yet had a verbatim release of the questions asked and a publication of the original tables.  It's one of the largest polls conducted in Australian history and I cannot even use it in my voting intentions aggregate because no primary votes have been released! (Edit: some have now.)

But that said, it is clear that turnout for the survey will be at least reasonably high, perhaps very high - it could still at this rate get to, say, 75%.  It is higher than for other postal vote processes in Australia, which were never that comparable as they mostly involved more obscure issues.  We're also not seeing anything yet in the last week or so to suggest that the narrowing of support for Yes being found by some polls earlier on has continued, nor anything in the public debate to suggest that it should.

Perhaps the campaign doesn't matter all that much and people are just answering the question.  But assuming it does matter, I have found it difficult to judge the quality of the campaign because I view the entire No case as completely unjustifiable, and I have had to make severe adjustments to even try to account for this.  With a handicap larger than mine would be at golf applied, I thought that the No case had a good run of the media cycle early in the response phase, but has looked silly even by its own standards in the past several days, including being seen to contradict itself on free speech by whinging about Macklemore and being reduced to scouring social media to advertise evidence that it was being hated.  So if some of the move back to Yes implied by the Sky ReachTEL is real, it's not too hard to say where it might come from.

I'll update this article over the next several days with more comments on new polling as it comes out.  I've meant to also write about security issues in the process but I have been extremely busy lately and this isn't likely to change any time soon.  Comments on those remain very welcome!

Updates (Wednesday Oct 4): New today we have Essential (here, here, here) and this is the first attempt to cross-ask questions about in-principle support and actual voting.  The poll finds a 61-32 breakdown in in-principle support with a 66-30 breakdown among the (low if the ABS are correct) 47% who have already voted.  (The poll was taken from Wednesday to Sunday, so given postal delivery lag should ideally have had a slightly higher turnout than the ABS).  Those who voted reported voting Yes 64% No 30% "Prefer not to say" 6%.  There were actually more who opposed same-sex marriage but said they voted Yes than who supported same-sex marriage but said they voted No.  However, Yes lost more votes to "prefer not to say" (whatever that is).

There is also some fossilised internal poll stuff being spruiked by Miranda Devine - see comments.

Week Two Update

The week two ABS update estimates only another 5% have been received in the past week, bringing the total up to 62.5% as of Friday.  This will probably tail off further from this point, so I am still expecting something around the low to perhaps mid 70s.  Unless the ABS are making a serious error then this new figure confirms that the turnout figures in some of the polls were too high.

There is no new reliable polling (though more unsubstantiated Devine spruiking of No campaign internals has been sighted) with Essential this week not polling the question. I've just taken one for the team by watching 34 minutes of Q&A (aaaaaaaarrrrrrggggghhhhh!) to determine that Michele Levine of Roy Morgan said that according to their polling same-sex marriage had over 80% support prior to the debate surrounding the postal survey but that this had dropped to a level consistent with a Yes vote of 60% or more.  This should be treated with caution since Morgan's only published polling on this in the last few years was an SMS poll with an element of opt-in and even that only got a 76% Yes vote.

Added Oct 14: Some more details re Morgan polling here.  Note that it actually implies a Yes vote of higher than 61.5% given that 21% either didn't answer or aren't voting.  How much higher is a matter of speculation.

Week Three Update

The week three ABS estimate update adds another 5%, the same as last time, bringing the total up to 67.5% of all enrolled voters (10.8 million)  This hasn't tailed off in the way I expected, though it's always possible the tailing off has been lost in the rounding.  Because the number of surveys estimated to have been returned is rounded to the nearest hundred thousand, in theory there could have been just over 700,000 this week and just under 900,000 last week (or, less probably, the other way around).  Indeed, we don't know for sure whether these estimates are necessarily accurate to the closest or even second closest hundred thousand.

Hitting the turnout bullseye wasn't too difficult for YouGov which reported 67% of its sample had voted with 61% yes, 35% no.  Nothing new from Essential this week.

Newspoll has just come through reporting 65% of its sample had voted with 59% yes, 38% no. On the in-principle support-oppose question it has 56-37 for Yes (compared to 57-34 in its previous poll).  The 35 points that have not voted include 19 points claiming they definitely will and 6 points claiming they probably will, which would make a total 90% turnout.  Those who have not voted split 49-37 to Yes.

Week Four Update

As noted in comments, the week four update has 11.9 million forms returned (that's 74.5%!)  The ABS says only 300,000 were received in the last week, meaning that last week's estimate was 800,000 short.  The explanation for the difference would be errors in the ABS's weight-based method for previously estimating turnout, so really there has been a big tailing-off this week.  The question now is whether there will be a late rush that might lead to a further pickup and push it to above 80%, or whether there might be only, say, 3-4% still to come.

Essential has a 60-34 yes-no response among those who say they have voted, which is 75% of their sample (a figure that is looking very good after today's release!), with another 8% still saying they definitely will vote.

Week Five Update

The week five update has 12.3 million forms returned (77%).  I have seen no new polling this week yet. There was, however, a report that only 0.3% of the returned forms are blank or invalid.