Thursday, March 23, 2017

If Ukraine don't back down, they must be banned from their own Eurovision

Apologies for a Eurovision post as early as March, but the events of the last couple of days have been truly extraordinary.  First of all, the Ukrainian authorities announced that the Russian entrant wouldn't be allowed into the country to compete in this year's contest (taking place in Kiev), because she performed in Crimea without their permission.  Russia of course now regards Crimea as an integral part of its own territory, so whatever you may think of that state of affairs, it would have been totally unrealistic to expect a Russian citizen to apply for Ukrainian permission before going there.

I suggested on Twitter yesterday that the EBU couldn't possibly accept a Ukrainian veto on who can compete for Russia, and that if there was no U-turn they would have to think about the unprecedented step of allowing Julia Samoilova to compete via a live feed.  After a little indecision, the EBU came to precisely that conclusion today.  But now the Ukrainians are apparently attempting to veto even that solution, and are saying that it would somehow be a breach of Ukrainian law to broadcast the Russian song if it is performed under these circumstances.

There is a very clear precedent covering this scenario.  In 2005, Lebanon seemed set to join the contest, and selected a beautiful (if a tad old-fashioned) entry in French called Quand tout s'enfuit.  I was really disappointed when they were forced to withdraw, but the logic was impossible to argue with - Lebanese law forbade the broadcast of the Israeli entry, and that would have made a mockery of the whole contest.  Exactly the same principle applies here.  It's probably too late to strip Ukraine of their hosting rights, but if they refuse to broadcast the properly-selected Russian entry, they shouldn't be allowed to participate in their own contest.  If they don't back down and they aren't banned, the integrity of the competition (stop laughing at the back) will be fatally undermined.

Tuesday, March 21, 2017

If Theresa May can only "win" a referendum by stopping it taking place, then...

Just a quick note to let you know that I have a new article at the TalkRadio website about Theresa May's outrageous bid to overturn the long-standing British government policy that Scotland can only remain in the UK by democratic consent.  You can read the article HERE.

CONFIRMED : Last night's ludicrous Sky "poll" was not weighted by EU referendum vote

As you may have seen, Sky News made an exasperating attempt last night to distort the referendum debate with a wildly unreliable online "poll", conducted by themselves and using their own paying customers as respondents, which purported to show that Theresa May is significantly more popular in Scotland than Nicola Sturgeon - a finding that is light-years out of line with recent properly-conducted polls from firms affiliated to the British Polling Council. 

The numbers were so patently absurd that I didn't think they even warranted the effort of a blogpost, although I did post a tweet pointing out that it was a junk poll and should be disregarded.  That prompted a reaction this morning from Harry Carr, head of "Sky Data", who insisted that it was a nationally representative poll.  He also produced datasets which showed that some weighting had been done - but there was no obvious sign of many of the political weightings that are standard in Scottish online polls, such as by recalled indyref vote, recalled EU ref vote, or recalled Holyrood vote.

As the poll bears all the hallmarks of having far too many Leave voters in the sample, I asked Harry a simple question - had he weighted by EU ref vote?  His answer : No.  He had weighted by recalled 2015 general election vote, but not by EU ref vote.  I strongly suspect that also means he didn't bother weighting by recalled Holyrood vote or by recalled indyref vote.

There's your explanation for the poll's nonsense results right there.  A telephone or face-to-face poll can possibly get away without doing proper political weighting, and just relying on demographic weighting.  But an online poll - no chance.  Online polls are different because you know in advance that you're drawing from an unrepresentative pool of potential respondents - Sky customers, for example, may well have political leanings that are different from non-Sky customers, and you have to carefully weight to correct for that.  I literally can't think of a single British Polling Council firm that would have attempted to conduct an online poll in the way that Harry has done.  It also looks like he didn't bother weighting by country of birth - a failing that he has in common with only BMG.

I stand by my original assessment - junk poll, ignore.

By the way - here's a challenge for Harry.  Conduct a Scottish voting intention poll, and publish it even if it puts the Tories in the lead.  Then try to keep a straight face when you defend your methodology.  Go on, I dare you.

Monday, March 20, 2017

The Greens' vote in favour of an independence referendum is fully consistent with their election manifesto

The latest desperate tactic of unionist politicians and journalists is to attempt to deligitimise the Greens' forthcoming vote in favour of an independence referendum by suggesting that it is somehow a betrayal of their own Holyrood manifesto from last year.  A frequently-heard claim is that the manifesto committed the party to only back a referendum if "one million" signatures had been collected demanding one.  That is completely and utterly untrue.  For one thing, you will search that manifesto in vain for the figure "one million", because it's not mentioned anywhere.  There isn't even a commitment that ANY signatures at all have to be collected - all that is said is that the Greens' "preferred way" of triggering a referendum is by an "appropriate number" of people signing a petition.  The phrase "preferred way" was an implicit acknowledgement that the Greens were going to continue to be a minority party within a parliament elected by proportional representation, and that holding a referendum would therefore require listening to the "preferred ways" of other parties, and then reaching an agreement on which one would be adopted.  Absolutely nothing in the manifesto precludes the Greens from backing an option that is not their own first preference.

As far as the one million figure is concerned, it's true that Patrick Harvie was asked what an "appropriate number" might be, and one million is what he came up with.  But the unionists can't have it both ways - if they're going to treat a manifesto like a sacred text and beat a party over the head with it, they actually do have to look at the words that are contained within it, and not at extraneous material.  There is no definition provided in the manifesto for the phrase "appropriate number" - it could be a million signatures, it could be twelve.  It could certainly be a low enough figure to be achieved comfortably within an afternoon or two.

As I understand it, the Greens' own explanation of their current stance rests primarily on the part of the manifesto that stated in general terms that if a referendum is to happen, it must come about by "the will of the people".  The will of the Scottish people as expressed in the referendum last June is to remain within the European Union, which is no longer compatible with their earlier desire to remain within the United Kingdom.  A second independence referendum is therefore the only way of resolving the incompatibility, and determining what the will of the people actually is when faced with a straight choice between the UK and the EU.  That logic looks watertight to me.

I think most of us would agree that it would have been better if the Green manifesto had used stronger wording, and had explicitly referred to the possibility of an early referendum being triggered by Brexit.  Nevertheless, the wording was more than adequate, for the following reasons -

* It acknowledged the prospect of a second independence referendum, and committed the Greens to campaigning for a Yes vote when it takes place.

* It did not exclude the possibility of a referendum taking place within the 2016-21 parliament.

* It imposed no specific pre-conditions on Green support for a referendum within the 2016-21 parliament.

Sunday, March 19, 2017

HALF of Scottish public want an independence referendum within just TWO YEARS, confirms extraordinary Panelbase poll

Today brings word of the first full-scale Scottish poll to be wholly conducted since Nicola Sturgeon fired the starting-gun for a second independence referendum.  It's a Panelbase poll for the Sunday Times, and although the datasets have yet to appear, it looks as if the question about the timing of the referendum used identical wording to the last Panelbase poll for the same client a few weeks ago.  As I noted at the time, that wording is extremely poor.  Respondents are asked to choose between a referendum in "the next year or two", a referendum "in about two years", or no referendum "in the next few years".  The latter timescale implies a period of longer than two years, which means that people who want a referendum in three years' time (2020 has, after all, been mentioned as a possible compromise date) do not have an option that represents their views - they're effectively forced to choose an option they don't really believe in.  However, within those inadequate confines, there is a roughly even split between those who say they want a referendum within two years, and those who say they don't want one within the next few years - exactly as there was in the last poll.

The combined support for the two 'within two years' options is 50%, while support for 'not within the next few years' is 51%.  The apparent incompatibilty of those numbers is caused by the effect of rounding.  That suggests support for an early referendum on the raw numbers is fractionally below 50%, perhaps similar to the 49.4% recorded in the last poll - but that would, of course, be well within the standard 3% margin of error, meaning it's impossible to know whether the true figure is a little above 50%, or a little below.

In spite of the continuation of the basic 50/50 split, this isn't a no change poll by any means - there has been considerable movement within the half of the sample that wants an early referendum, with a sharp 5% increase in support for the 'hardline' option of a referendum "in the next year or two" while Brexit negotiations are still ongoing.  That figure now stands at 32%.  There has been a corresponding 5% drop in support (to 18%) for the more 'moderate' option of a referendum "in about two years", after negotiations have been completed.  Ironically, the latter option is closest to Nicola Sturgeon's own stated plans, so almost a third of the population actually feel that she is not moving quite fast enough.  You probably won't hear about that on the mainstream media, though.

I don't pay the Murdoch Levy, so in the absence of the Panelbase datasets I'm not sure whether respondents were also asked whether Theresa May should grant a Section 30 order allowing the referendum to take place on the same basis as the 2014 vote.  However, there is a Britain-wide ComRes poll out today which asked whether respondents agreed or disagreed with the following statement -

Theresa May should insist that any second Scottish referendum on independence takes place only once Britain has completed the process of leaving the EU.

The results among the Scottish subsample (excluding Don't Knows) were...

Agree : 48%
Disagree : 52%

Subsample results cannot be regarded as reliable, of course, but as it happens those numbers are bang in line with the most recent full-scale Scottish YouGov poll (conducted mostly before Nicola Sturgeon's referendum announcement), which found that 52% of the public think the London government should agree to a referendum if Sturgeon asks for one.

Panelbase also asked a voting intention question on independence itself...

Should Scotland be an independent country?

Yes 44% (-2)
No 56% (+2)

Some unionists are beside themselves with excitement at that result, taking it as proof that the YouGov poll showing Yes 43%, No 57% wasn't such an outlier after all.  Well...up to a point, Lord Copper.  It's true that we now have a first non-YouGov poll since autumn 2014 to show the Yes vote slightly lower than the 45% actually achieved in Indyref 1.  It's also true that YouGov no longer looks like an extreme outlier, but it is still very much at the No-friendly far end of the spectrum.  YouGov's inexplicable refusal to include 16 and 17 year olds in their sample may in itself explain the difference between their findings and Panelbase's.

As far as Panelbase are concerned, there were signs even before today's poll that they might be starting to slot into the No-friendly zone - the previous poll from the firm had Yes stuck on 46%, even though polls from Ipsos-Mori and BMG at around the same time showed Yes surging to 48-50%.

Of the last seven polls conducted by all firms, three (two from BMG and one from Ipsos-Mori) have shown an unusually high Yes vote, two (one from Panelbase and one from Survation) have shown a figure within the familiar range of recent times, and two (one from YouGov and today's from Panelbase) have shown an unusually low Yes vote.  It would be totally irrational to conclude on the basis of that evidence that there has definitely been a drop in the Yes vote - the opposite may have happened, or there may well have been no change at all.

*  *  *

SCOT GOES POP POLL OF POLLS

Should Scotland be an independent country?

Yes 46.4% (-0.4)
No 53.6% (+0.4)

(The Poll of Polls is based on a rolling average of the most recent poll from each firm that has reported at least once within the last three months. The firms included in the current sample are Panelbase, BMG, Ipsos-Mori, YouGov and Survation.)

Saturday, March 18, 2017

How an early Scottish election can be triggered

Opinions differ on how possible/probable the options of a consultative referendum or early Holyrood election are in the event that Theresa May remains intransigent.  Brian Taylor of the BBC, for example, acknowledges that both options are on the table, but insists that both are "unlikely" because Nicola Sturgeon would regard them as "gestures".  Whether he's being led by his own assumptions and preconceptions, or whether he's been reliably briefed to that effect, is anyone's guess.

However, as there seems to be some confusion over exactly how an early Holyrood election can be brought about, it might be worth refreshing our memories by looking at the relevant part of the Scotland Act.

"The Presiding Officer shall propose a day for the holding of a poll if—

(a) the Parliament resolves that it should be dissolved and, if the resolution is passed on a division, the number of members voting in favour of it is not less than two-thirds of the total number of seats for members of the Parliament, or

(b) any period during which the Parliament is required under section 46 to nominate one of its members for appointment as First Minister ends without such a nomination being made."

The crucial word is "or". Options a) and b) are either/or - they don't both have to be met.  In other words, if the First Minister resigns and is not replaced within 28 days, an election is triggered without the need for a two-thirds majority, and the unionist parties would not have the opportunity to form a blocking minority.

There is, however, a small catch.  If there is an election for First Minister during the 28 days and only one unionist candidate is nominated, there will be an "affirmative vote" and that person will be rejected.  If, however, at least two candidates come forward (say, Ruth Davidson and Kezia Dugdale), it wouldn't be possible to stop one of them from being elected.  That's basically because the rules are a bit silly.  If Davidson received the votes of the 31 Tory MSPs, and Dugdale received the votes of the 24 Labour MSPs, the vote would be declared valid and Davidson would technically become First Minister.  That's not a problem in itself, because the "Davidson government" would, within a few short days, be ousted by a vote of no confidence.  However, that would simply start the 28-day process all over again, and in theory we could go round in circles into infinity.

In practice, that wouldn't happen, because the unionist parties would be worried about making themselves look ridiculous, and people would be chanting "politics is not a game" at them.  However, we should probably be prepared for them to attempt the stunt at least once.  Personally, I don't think that would be the end of the world.

Friday, March 17, 2017

Theresa is tanking : blow for autocrat PM as YouGov poll shows pro-independence parties have an absolute majority of the vote

I have to say I find it pretty incredible that a YouGov poll in which the headline Yes vote was unusually low has been so good for us in a variety of other ways. As I've already mentioned, it shows a 52% to 48% majority in favour of Westminster allowing an independence referendum to be held (a finding studiously ignored by a mainstream media hellbent on sticking with their beloved "the Jocks don't even want a referendum" narrative, in defiance of all evidence). A batch of newly-released figures from the poll show increasing support for the SNP, improved personal ratings for Nicola Sturgeon, a drop in popularity for both Theresa May and Ruth Davidson, and a giant raspberry for the notion that Scotland needs the UK more than it needs the EU.

Let's start with the Holyrood voting intention numbers, which shows a boost for the SNP vote on both ballots, an absolute majority of the vote for the SNP on the constituency ballot, and an absolute majority for the pro-independence parties on the list ballot.  It also suggests that the once-dominant Labour party is now in severe danger of slipping to fourth place on the list vote, behind even the Greens - although that hasn't happened quite yet.

Constituency ballot :

SNP 51% (+3)
Conservatives 24% (-1)
Labour 14% (-1)
Liberal Democrats 6% (n/c)
Greens 4% (+1)
UKIP 1% (n/c)

Regional list ballot :

SNP 40% (+1)
Conservatives 25% (+1)
Labour 14% (n/c)
Greens 12% (+1)
Liberal Democrats 5% (-1)
UKIP 2% (-2)
RISE 1% (n/c)

The absolute majority for pro-indy parties on both ballots may be of some interest as we ponder the possibility of an early Holyrood election functioning as a de facto independence referendum.  And once again, I don't think it's unreasonable to pose the question - given that the headline Yes vote in this poll looks implausibly low, and given that YouGov didn't even bother interviewing 16 and 17 year olds, is it just possible that the above figures may even underestimate the SNP?

As far as personal ratings of leading politicians are concerned, there are two ways of judging the pecking-order - one is based on the percentage of respondents who have a positive view of each politician, and the other is a net rating, calculated by subtracting the percentage of respondents who have a negative view from those who have a positive view.  Nicola Sturgeon has the lead on one measure, and is in a close second place on the other - but she has improved her standing in both.  Meanwhile, Ruth Davidson has gone backwards on both measures, and Theresa May's net rating has dropped significantly, entirely due to a sharp increase in the number of people who view her negatively.  There's still a tendency south of the border to talk about the "Theresa May honeymoon", but in Scotland that's something we refer to in the past tense - the more people see her, the less they like her.  My guess is that Hard Brexit and her antics in attempting to block an independence referendum will eventually see her hit Thatcher-style levels of unpopularity, although admittedly she still has a long way to go before that happens.

Positive ratings :

Nicola Sturgeon 53% (+3)
Ruth Davidson 47% (-2)
Theresa May 37% (+2)
Kezia Dugdale 26% (+3)
Jeremy Corbyn 13% (-7)

Net ratings :

Ruth Davidson +18 (-7)
Nicola Sturgeon +16 (+5)
Theresa May -10 (-5)
Kezia Dugdale -16 (+5)
Jeremy Corbyn -56 (-21)

It's been speculated in recent elections and referendums that supplementary questions may sometimes give a better indication of how a vote is likely to pan out than the headline voting intention question.  If there's some truth in that, the Tory government should be deeply concerned by the response to a question that asks whether the EU or the UK is the more important trade partner for Scotland - which in many ways goes to the heart of what the next independence referendum will be all about.  Respondents were split down the middle - with one-quarter of No voters from 2014 saying that the EU is more valuable.

*  *  *

I was tickled by the Herald's write-up of the "everything but the kitchen sink" list of pre-conditions laid down by defeated opposition leader Ruth Davidson for the elected government being allowed to hold a referendum.  One is that there has to be agreement across the parties - which means that even if the Tories and Labour agreed, Willie Rennie would still have a veto.  (Thank heavens the Scottish Senior Citizens' Unity party is no longer around, otherwise even their bloke would be able to single-handedly prevent his millions of fellow citizens from having a say.)

I'm still not convinced that Davidson has put quite enough roadblocks in the way, though.  Allow me to suggest a few more perfectly reasonable pre-conditions -

* There cannot be an independence referendum until Bashar al-Assad gives the nod.

* There cannot be an independence referendum until Nicola Sturgeon pays a £100 million deposit "in good faith".

* There cannot be an independence referendum until a psychic medium checks to make sure Princess Diana is OK with it.

* There cannot be an independence referendum until 200 billion signatures of Scottish residents have been collected and verified.

* There cannot be an independence referendum until NASA confirms there are no asteroid collisions due until at least 2150, because Theresa May mustn't be distracted in the face of impending global catastrophe.

Thursday, March 16, 2017

What are Nicola Sturgeon's options for holding a vote on independence without Westminster's agreement?

Nicola Sturgeon said tonight she was determined to hold a vote on Scotland's future on the reasonable timescale she has already set out, and that she would "consider her options" if Theresa May tries to block it (which is clearly what will happen).  So what are the options for holding a vote without a Section 30 order, and which is Sturgeon most likely to plump for?

1) A consultative referendum without Westminster permission.  This would probably be the best option IF any legal obstacles can be overcome (opinions differ on how easy or difficult that would be).  It would essentially be lose/lose for Theresa May - if the Tories and other unionist parties actively campaign in the referendum, they will give it legitimacy and they may as well have just granted the Section 30 (and they will also look stupid and anti-democratic for having not done so).  But if they boycott the referendum, a Yes vote will be assured, quite possibly on a respectable turnout, and the moral authority of the 2014 result will be surrendered.

2) An early Holyrood election to obtain an outright mandate for independence, with the SNP and Greens placing an explicit commitment to independence (without any need for a further referendum) in their manifestos.  This option has the beauty of being legally watertight - there's nothing London can realistically do to stop it, short of dismantling devolution.  It would probably mean we'd be chasing 50%+ of the popular vote on both the constituency and list ballots, which is a very tough target - but remember the SNP and Greens took an outright majority of votes in Scotland at the UK general election in 2015.

3) SNP MPs or constituency MSPs (or both) resign en masse, and trigger by-elections across Scotland to obtain a mandate for independence.  This idea has been floated a few times, but is unlikely to happen because a Scotland-wide mandate would be required to bring about independence.  The SNP (and allied "independents") hold all but three Scottish seats at Westminster - but those three would be enough to ruin the legitimacy of any mandate, unless the vote obtained is implausibly decisive.  As the option of a Holyrood general election exists and is superior, there's simply no point in going down the by-election road.

4) Play the long game, implicitly accept Theresa May's decision, and wait until 2021 to obtain a mandate with which to beg her (or her successor) for a referendum all over again, with no guarantee that she will prove to be any more reasonable.  This is exactly what May and Davidson want us to do - which might be a little clue as to why it's a very, very bad idea.

Verdict : Obviously it'll either have to be the consultative referendum or the snap Holyrood election.  The only other way forward I can see would be an early Holyrood election to obtain an even more emphatic mandate for a Section 30 order than the one we already have - but if Theresa May is just going to keep mindlessly saying no, what's the point?  We'll have to take the bull by the horns eventually, and dragging voters to the polls one more time than is strictly necessary might prove counter-productive.

*  *  *

Random thought : Is Scotland the only "democratic" country in the world where the defeated opposition leader gets to announce what the elected government won't be allowed to do?

This is now a hostage situation - Theresa May attempts to abolish Scottish democracy...and the Scottish Government must take bold action to stop her

If the 'sources' chatter from journalists is correct, Theresa May will this afternoon reverse decades of British government policy and announce that Scotland does not have the right to democratic self-determination.  There is, she will apparently say, no longer any democratic path to independence - the UK government has unilaterally decided that Scotland is to remain in the UK, regardless of the views of the Scottish people.

Two obvious conclusions follow from this -

1) In any universe where the media do not pat her on the head for her constant contradictions and U-turns, Ruth Davidson's position as Scottish Tory leader would now be utterly untenable.  She has stated on numerous occasions that, while she is vigorously opposed to a second independence referendum, it would be wrong for London to block one if the Scottish Parliament voted in favour.

2) In my view, the Scottish Government must now start stating openly that they will ensure the Scottish people are allowed to make a decision on independence, even if a Section 30 order is not granted.  This could take the form of a consultative referendum, or of an early Holyrood election in which the SNP manifesto seeks an outright mandate for independence.  I'm reasonably sure contingency planning must have been done for one of those options, but it's still important to make a public announcement as soon as possible, to prevent the narrative being established that "the Jocks asked for a referendum, the headteacher said no, end of story".  There may be the temptation to go through the motions of formally requesting a Section 30 order, waiting for a formal rejection, and then formally requesting a rethink, etc, etc...and that would be a great mistake.  The Scottish Government must not allow themselves to look impotent by running around in circles to no great effect, especially when they have high-ranking cards they could be playing. 

Wednesday, March 15, 2017

YouGov poll : Hammerblow for Theresa May as Scottish public demand Westminster MUST allow an independence referendum

The datasets for last night's downright weird YouGov poll are now out, and there is actually some good news to be found in them.  (Most of this was probably already revealed in the Times report long before I went to bed, but I don't pay the Murdoch levy so I was none the wiser.)  Most importantly, respondents were asked whether the UK government should "agree" to an independence referendum if Nicola Sturgeon asks for one.  Inconveniently for Theresa May's "the Jocks don't even want a vote" narrative, the answer was a narrow "yes".

If Nicola Sturgeon calls for a second independence referendum, do you think the UK government should or should not agree to one taking place?

Should agree : 52%
Should not agree : 48%

That's the first time I can recall seeing the question posed in that way, and it probably produces more meaningful results than the misleading "Should there be a referendum before Brexit negotiations are concluded?" questions we've seen in a few other polls (misleading because Nicola Sturgeon is not actually proposing such an early referendum).  It's also worth bearing in mind that YouGov's sample is, for whatever reason, unusually "No-heavy" - so if it turns out they're understating the Yes vote, it's not unreasonable to suppose that the majority in favour of a referendum is also somewhat bigger than they're reporting.  However, most of the fieldwork for this poll was conducted before Nicola Sturgeon actually went ahead and called for a Section 30 order to be granted, so it remains to be seen what effect that development will have on public opinion.

The other piece of good news looks like bad news at first glance - by a 60-40 margin, respondents say the Scottish Government should not campaign for independence over the next two years.  That represents substantial progress since exactly the same question was asked a few months ago, when the margin was a much bigger 64-36.  I suspect Nicola Sturgeon's announcement may have a further impact on those numbers as Yes supporters rally behind her decision, but time will tell.

Let's turn now to the really burning question : is there any explanation in the datasets for the oddity of the Yes vote in this poll being lower than in any poll conducted by any firm since the autumn of 2014, in spite of the fact that a telephone poll only last week put Yes in the lead?  To a limited extent there is.  To my surprise, and utterly incomprehensibly, the datasets confirm that YouGov have stopped interviewing 16 and 17 year olds, even though they must know that the minimum voting age at the next referendum will almost certainly be 16, just as it was in the last one.  Now, it's true that 16 and 17 year olds make up only a relatively small percentage of the electorate, and that a poll of over-18s probably isn't going to produce radically different results from a poll of over-16s.  But it might well make a small difference.  If the correct electorate had been polled, it's quite possible that the Yes vote would have been 1% higher and the No vote would have been 1% lower.  So it's entirely wrong for YouGov, the Times and the wider mainstream media to present Yes 43%, No 57% as being reliable and relatively precise voting intention numbers.  Perhaps even more importantly, it's grossly misleading to suggest that the Yes vote has fallen slightly since the last YouGov poll, given that 16 and 17 year olds were interviewed last time around.  If the two polls had used the same minimum age, they might well have produced identical results.

As I've said before, I don't think this is a conspiracy from YouGov - I just think it's a mixture of Anglocentricity and institutional laziness.  Because they usually poll over-18s only, it seems they simply can't be bothered making special arrangements for Jock polls.  If the voting age for Westminster elections had been reduced to 16 in 2014, there's no way on Earth they'd still be polling the wrong electorate a whole three years later.

There are no other obvious smoking guns in the datasets - the question asked looks fine, and is exactly the same one YouGov have been using for years.  Very little weighting has had to be done by recalled 2014 referendum vote, although that in itself raises a few questions, because it must mean that YouGov are sending out invitations in a very careful and extraordinarily controlled way.  So if there is something fishy going on, perhaps it's at the invitation stage.  The notorious "Kellner Correction" made an artificial adjustment to the sample of SNP voters to make sure that they were the "right sort" of SNP voters - could something similar be happening now, but this time using the invitation stage as a filter?  It's possible, but it's also completely impossible to tell, because that sort of information isn't publicly available.

By far the most suspicious feature of the datasets (although not proof of dodgy methodology) is that the No vote is much stronger among the least affluent respondents.  That's entirely counterintuitive, and is the opposite of what we see in most polls.  OK, sometimes you just get weird subsamples which cancel each other out to some extent (for example too many female Yes voters in a sample might be partly offset by the presence of an excess number of male No voters), but the problem is that less affluent voters are generally less likely to take part in polls, and therefore their responses usually need to be weighted up, while the responses of affluent voters are weighted down.  That weighting usually works in favour of Yes, but in this particular case the opposite is true - the No-friendly raw sample of 397 less affluent respondents has been upweighted to count as 493 'virtual' respondents.  So if there is something wrong with the raw sample (and it's hard to escape the conclusion that there must be), that problem will have been sharply magnified by the weighting.

To give an example of what I'm talking about - in the most recent Panelbase poll, the Yes vote among the less affluent part of the sample was 11% higher than among the more affluent part.  A very similar pattern was seen in the Ipsos-Mori poll last week, and the BMG poll at the weekend.  And yet in the YouGov poll the Yes vote is 12% lower among the less affluent than it is among the more affluent.  It simply doesn't pass the 'smell test'.