Tuesday, 3 March 2015

Mapping the SNP surge - a return to Scottish constituency betting

There are now 9 ½ weeks to go to the general election, and if the polls are to be believed, Scottish Labour are going to be as screwed as Kim Basinger was in the film of that name (though at present it seems unlikely that whipped cream or strawberries will be involved).  But no votes have been cast or counted yet, and there is still time for the eventual result to change.  Tomorrow we are due to have some more polls from Lord Ashcroft, including some in Scotland.  Where do the Scottish constituency markets stand now?
Here are the bookies' prices as they stand today:
As on previous occasions, I have organised them by reference to the best price odds for the SNP taking the seats.  The SNP are now odds-on favourites in 41 seats.  The long period when you could back the SNP at odds-against in defiance of the polls giving them epic leads is now sadly over.
But does any value remain?  Actually, I think there is.  Lord Ashcroft has provided us with some constituency polls already:

Where the SNP have a double digit lead, that will be difficult now for Labour to overcome, even if they can squeeze other parties further.  Despite that, the SNP are still as long as 1/2 in Cumbernauld, Kilsyth & Kirkintilloch East and Glasgow Central (and the 1/3 with SkyBet in Inverness, Strathspey, Badenoch & Nairn looks very long considering the SNP registered a 29% lead with Lord Ashcroft).  These all look like good bets to me.

Of those 41 seats where the SNP are odds-on favourites, the price is longer than 1/2 in 19 of those seats.  On present polling it is my firm belief that there is a better than two in three chance that we will see more than 22 SNP MPs elected in May.  I make it at least an 80% chance from this point that the SNP will exceed 22 seats in May and possibly higher.  So there must be some value in those relatively longer priced seats where the SNP are favourites as well if I am correct.
We come back to the same problem as always - how to find the seats where the SNP are strongest.  It's really galling to lose odds-on bets. 
It is apparent that the SNP has put together a new coalition of voters that breaks down previous allegiances.  However, it is not yet fully apparent how that coalition is comprised.
Among with many others, I have had a go at modelling this new coalition, as explained in these two lengthy posts:
That model did reasonably well when tested against Lord Ashcroft's first batch of constituency polls, so I'm now working on the assumption that I'm along the right lines (but please note all the health warnings in that second piece).  The Lib Dem collapse in constituencies where they are not in contention has been still more extreme than I imagined possible.  If anything, I seem to have underestimated the scale of the transfer of those former Labour supporters who voted Yes to the SNP. 
Set against that, there are straws in the wind that some Conservatives in particular are considering tactical votes for Labour to keep the SNP out: "there have been reports from Conservative canvassers and activists that some of their traditional supporters are prepared to do the unthinkable and vote Labour in areas where the Tories are seen to have no chance of winning."

This anecdotal evidence would seem to be backed up by Ruth Davidson's spring conference address:
With this in mind, I expect unionist opposition to the SNP to coalesce at least partially around the incumbent.  This process may be accelerated if Lord Ashcroft polls some of the more confused constituencies, enabling the chief challengers to draw up suitable bar charts.
These cross-currents point towards the better bets on the SNP being in constituencies with a relatively strong Yes vote and a relatively weak Conservative presence.  On that basis Inverclyde at 8/13 looks good value, as does Paisley & Renfrewshire North and Lanark & Hamilton East, both at 8/11 (though I should note that the SNP seem unusually fractious in Paisley & Renfrewshire North).    Given that I have apparently underestimated the transfer of Yes votes to the SNP, Rutherglen & Hamilton West is possibly worth a sporting bet at 3/1 also.  As I argued last time I looked at Scotland, the SNP may take this seat when others which require far smaller swings might resist.  
Where to avoid betting on the SNP?  Or put another way, are there now some seats where it might be worth backing another party?  If Labour are going to be able to harvest some Conservative votes, they will prove tougher opponents, especially where the Yes vote was smaller.  For example, I am wary of betting on the SNP in Aberdeen South, Stirling and Edinburgh South West.  Ayrshire Central and Ayr Carrick & Cumnock look as though they should fall to the SNP, but their odds-against prices may be correct if Labour can persuade enough Conservatives that they are unionists first.
I'm not betting on the SNP's opponents in these seats, because my concerns are just too tentative at this stage.  That may change tomorrow if Lord Ashcroft has polled in areas that were more resistant to No. 

1 comment:

Anonymous said...

I think you can pour yourself a whisky, Antifrank :)