Originally Posted by
ItJustMyOpinion:
“The last twelve opinion polls as a graph.
https://twitter.com/May2015NS/status/592722584107667457
So the polls don't really tell us anything apart from both party's are still neck and neck and neither have managed to pull ahead.
YouGov, Populus, PanelBase say Labour are winning.
Survation, ComRes, ICM, Ashcroft, Opinum say Conservatives are winning.
Looks more like a battle for which polling company is going to win, rather than which party.
What's the difference between their methods, which has been more reliable in the past, anyone know?”
As far as I've been aware, ICM have generally been considered the 'gold-standard'. but looking at the polling in the last election it appears that many of the pollsters polled very similar results. In fact, it looks as if MORI may have polled the closest to the actual result:
Quote:
“5th May 2010
Ipsos MORI/Evening Standard
Lab: 29%
Con: 36%
LD 27%
Other: 8%”
This was the last ICM poll of the GE:
Quote:
“3–4 May 2010
ICM/The Guardian
Lab: 28%
Con: 36%
LD: 26%
Other: 10%”
The actual GE result:
Lab: 29.7%
Con: 36.9%
LD: 23.6%
Other: 9.8%
What pollsters last time out messed up was the LD share; all pollsters vastly over-estimated the support the LDs would get, polling them generally between 26%-28%, with the party actually losing 5 seats in the real GE, and polling at 23% - 7 percentage points below their highest polling mark (30%, in April with Angus Reid and a couple of other pollsters).
On ICM, I think the UKIP vote (and for that matter, the LD vote) could potentially slip them (and Ashcroft, too) up when polling. Apparently their recent poll shows many 2010 LDs moving to the Conservatives, more so than Labour which is a highly unusual sample. ICM post-GE 2010, got IndyRef and the EU elections wrong too - in the EU elections, they polled the Tories to come top, and Lab in third place as far as I recall - when the result was UKip, Lab, and Con. I think pollsters such as ICM and Ashcroft are underestimating the UKIP vote - I mean UKIP aren't getting 0 MPs at a GE - if worst comes to surprisingly the worst, Carswell will
definitely hold Clacton - and other pollsters (well, mainly Survation tbh) are overestimating the UKIP vote. I sincerely doubt UKIP are going to poll 19% at the GE.
Survation and Ashcroft are relatively new kids on the block to polling, so this election will be the first time they're tried and tested. I also think Panelbase haven't polled at an a election before, either.
As far as I'm aware in this term (2010-15), ComRes have changed/adjusted their metholodgy twice (in fact in light of getting the LD vote spectacularly wrong, I think all pollsters may have made methodological changes in 2010 after the GE), YouGov have changed theirs fairly recently, in the last month or so, and ICM appear to have kept their general method - in which they reallocate based on previous voting history at the last GE (as does Ashcroft I think). I'm unsure about the rest.