Archive for the 'Commons seat predictions' Category


June 8th 2017 is a day that the election predictor/modellers will want to forget

Wednesday, June 14th, 2017


It is little comfort to the election predictors/modellers that Wikipedia has now decided to record for posterity how successful they were in predicting the party seat outcome of GE17. The chart is above.

As can be seen only the YouGov model based on 50k+ of its own interviews came out of this well.

Throughout the campaign the forecaster/modellers aimed to produce projections of the party seat totals which, are course, based on the outcome of 650 separate first past the post elections in the different constituencies. This is sharp contrast to the BREXIT referendum or, say, the final round of the French election where it is a binary choice of two based on national totals.

The reason the GE17 modellers got it so terribly wrong was that their main data sources, the opinion polls, had, with one very honourable exception, a huge polling fail. Never was the saying garbage in garbage out so appropriate.

Virtually all of the models were following standard swing theory in their approach to seat predictions which meant a big error on top of everything with their LD seat projections. The party increased its MP total by 50% with a reduced national vote share. The exception was YouGov with its own exclusive and large polling data source.

A problem was the overwhelming CON landslide narrative which dominated everything and was reinforced by the adjustments almost all the pollsters had made following the GE15 polling fail. Any pollster that produced numbers that didn’t fit the general perception were attacked and their findings ignored.

This meant that sharp move away from the Tories after the manifesto saga was much less noticeable at the time and things like the consequential drop in CON 65+ support are only now being observed.

Lots of lessons from GE17 then which no doubt they will try to avoid next time.

The problem, of course, is that there is a huge appetite during a campaign for information on how the battle is going in terms of seats. Gamblers in particular are a key audience. The forecaster/modellers satisfy that need.

No doubt the Wikipedia table will be rolled out next time as a reminder to treat projections with caution.

Mike Smithson


The CON GE2015 target seat over-spending issue throws into question the mathematics of GE2017

Monday, May 1st, 2017

Keeping within the limits could make a difference

Becasuse so much of the effort to predict and analyse the next election is based on what happened in each seat at GE2016 we are in something of a quandary because of what we know now about the Conservative approach to constituency expense limits.

It is entirely possible that the Tories will be defending seats on June 8th that would not have been won if spending had been kept with the constituency limits.

Before GE2015 political scientists such as Prof John Curtice were predicting that the Conservatives would need a GB vote margin over Labour of 11% in order to achieve a majority. That they reached that target with a gap of just 6% was a remarkable feature of the election and how many punters got it so wrong.

Now thanks to the work of Channel 4’s Michael Crick and others we have a greater awareness of what went on in the election and this has been closely studied by the Electoral Commission which was very critical of the party.

    Thus we cannot now say with certainty that seat X requires a swing of Y% because the base figure, the GE2015 result, could have been different if spending limits had been kept to

What would have happened in that seat if expense limits had been adhered to and that is very much in the air.

This is all going to make betting on some single constituencies much more difficult and also raises questions the standard poll shares to seats calculations

If we do get news of action by the CPS before polling day that could also have an impact.

Mike Smithson


How Scotland and the LD collapse almost completely reverse the bias in the electoral system

Friday, May 29th, 2015

The dramatic shift in Britain’s political landscape

As we all know one of the constants in British politics over more than a quarter of a century has been that the electoral system has been “biased” towards Labour. Essentially for a given vote share the red team will have more MPs than the blue one.

Well the big news from May 7th is that that is all over and now the Tories will get more seats for an equal vote share than Labour. This is largely because of the total LAB collapse in Scotland and the Lib Dem decline.

The details are set out in illuminating article by Tim Smith of the University of Nottingham just published. He writes:-

“The largest contributor to this shift was third party victories, which swung from a Labour lead of 21 seats to a Conservative lead of 39 seats. The pro-Labour element of this had been mainly due to the fact that there had been far more Liberal Democrat MPs in seats where the Conservatives would otherwise have won than in those where Labour would otherwise have won. The collapse of the Liberal Democrats to just 8 seats eliminated most of this. Meanwhile, the SNP landslide in Scotland then pushed the bias in the other direction making Labour the primary victim of third party wins…

..In the UK system the boundaries are not deliberately gerrymandered by partisan redistributions, but nevertheless, they now very much favour the Conservatives whose votes are much more efficiently distributed. When the parties’ vote shares are equalized, Conservative wins waste far fewer surplus votes than Labour, with the latter now tending to pile up larger but ultimately unnecessary majorities in safe seats. The reason for this big increase in Conservative efficiency was caused by their very strong performance in the right places, i.e. marginal seats, and this was helped by the large number of first term incumbents standing for re-election for the first time. Labour did best in its safest English seats.”

This means, of course, that new boundaries would make the system even more favourable to the Conservatives.

Mike Smithson


The Thanet S & Hallam polls fail to move the markets & CON a 75% chance to win most seats

Thursday, April 30th, 2015

This is a bet on seat distribution not national vote shares

One of the big things to remember as we get close is that the final seat totals are not governed by national vote share in some apparently pure manner but on the specific outcomes in 650 separate constituency battles fought under FPTP.

Clearly this time the traditional ways of estimating seats from polls numbers have been smashed to smithereens by the political earthquake in Scotland. We should treat the politics north of the Tweed like we do with Northern Ireland which has operated in its own political eco-system for half a century.

In England and Wales where the big LAB-CON battles will take place it is not inconceivable that the party that’s second on votes could come on top.

So much is determined by local activity and strength of the party’s organisations.

When I look at the Ashcroft seat polls where the outcome is tight I always check the voting numbers before turnout filtering comes in. Quite often, like in yesterday’s Ashcroft Swindon South poll the Tories were 2 points adrift before this calculation.

As I’ve observed many times in the key marginals the party machines’ objectives are to ensure that even the most marginal voters vote.

My reading of the most seats outcome is that CON leads but not by very much. We are 55-45

Mike Smithson

For 11 years viewing politics from OUTSIDE the Westminster bubble


Even with Scotland will LAB still be able to win more seats than CON for the same national vote share?

Friday, April 17th, 2015

The academic experts are divided over electoral bias

One of the massive questions hanging over the May 7th outcome is the impact of what we are all familiar with – electoral bias that has meant that there’s a long history of LAB getting more seats for the same vote share than the Tories.

A lot of this has been down to Scotland where last time 41 of the 59 seats went to LAB. That clearly is not going to be repeated but what about the rest of the rest? What about in England and Wales?

At the packed Political Studies Association event in Westminster I got very different answers from two if the country’s leading political scientists. Professor Stephen Fisher of Electionsetc said he thought that it did not now exist. But his colleague, Professor John Curtice, said it did.

Curtice pointed out that even with a mass of Scottish losses LAB can win an overall majority with a 5% lead on GB vote share. For the Tories the required vote lead is in the 7-11% region depending on how successful the blue team is in its battles for current Lib Dem held seats.

Both Curtice and Fisher have been and are still are leading members of the small academic team which for the last two elections has produced the almost perfect projections for the exit poll.

I’m with Curtice. I can’t see that things have change so much in England and Wales in a manner that would impact dramatically on seat distribution. Remember that in 2005 the Tories led LAB on votes in England yet the latter won 92 more seats.

At 2010 the Tories had a vote lead in England of 11.4%. Yesterday’s Ipsos-MORI poll had LAB 2% ahead there.

Mike Smithson

For 11 years viewing politics from OUTSIDE the Westminster bubble


The big GE15 gamble is trying to work out what all the polling means in terms of seats

Monday, March 16th, 2015

And on that there is no clear cut picture

There is a huge divide both between academic groups and others like Martin Baxter’s long-standing Electoral Calculus.

Frankly I find it hard to work this one out and I guess that whatever happens it will be a big surprise on the night.

My long term GE15 bet has been CON ahead on votes – LAB ahead on seats.

Reminder the PB pre May 7th gathering tomorrow. The Shooting Star from 7pm

shooting star


Why the Tories could need to be 10% ahead in England and Wales just to stand still

Thursday, January 1st, 2015

What happened at GE2010 when you exclude Scotland

One of the reasons why the latest Electoral Calculus projection, see previous thread, appeared to be so good for LAB was the way Scotland and England/Wales were treated. This is the response I got from Martin Baxter on the computation:-

“The overall prediction is based on both the national (GB) polls and the Scotland-specific polls. For Scottish seats, the prediction is just based on the Scottish Westminster VI polls, and for England and Wales it is based on the GB polls (after allowing for Scotland).”

As can be seen from the chart the overall GB gap between CON and LAB was 7.3%. But because Labour did so well in Scotland last time excluding it makes a big different.This puts the overall gap between the two main parties in England/Wales at more than 10% which, theoretically, means that a gap at any level below that would see CON losing seats to LAB

The Tories, of course, are hopeful that they can make up some of this from the Lib Dems but as the Lord Ashcroft constituency polling has shown you can’t take gains from the yellows for granted.

Of course elections are not decided by national party popularity contests but by hard fought battles in each of the 650 seats where tactical and incumbency factors can come into play.

I plan to monitor the England/Wales swings closely in the coming four months. At GE2010 the Tories made nearly 100 gains there and they need to hold on to as many as possible.

Mike Smithson

Since 2004 – The view from OUTSIDE the Westminster bubble


Even though Baxter has SNP taking 47 of the 59 Scottish seats his latest projection has LAB just 5 short of a majority

Thursday, January 1st, 2015

I can’t quite work out how Martin Baxter is handling his monthly predictions given the sharp rise of the SNP. From his latest data, out last night, he appears to have made his usual national computation and then over-ridden the Scottish seat data with his Scotland specific seat calculation.

The result, as can be seen, is that in the model the SNP are set to take 47 of the 59 Scottish seats.

    What is very striking is that even taking out the LAB seat losses to the SNP in Scotland the overall national numbers have Ed Miliband’s party just five off a majority.

The element that is driving this is clear from his polling average on which the model is based. Some good numbers for Labour in several December polls have produced a LAB vote lead of 3.18%.

A feature which will attract attention is that his model does not account for by-elections and puts UKIP on zero seats.

Anyway this is a good way to kick off New Year’s Day. What do people think is going to happen on May 7th – something that we’ll be speculating about right through into the early hours on May 8th.

My guess is that polling accuracy and whether the Tories are understated will play a big part in our discussions. We’ll be reminded of 1992 when the party’s best final poll had them 0.5% ahead and John Major’s party came out with a majority on a vote share lead of more than 7%.

Will GE2015 be another GE1992? I’ll let you know at about 5am on May 8th.

Mike Smithson

2004-2015: The view from OUTSIDE the Westminster bubble