![\"\"](\"https:\/\/marriott-stats.com\/nigels-blog\/wp-content\/uploads\/2017\/06\/PollEffect-G4-170603-300x163.png\")
<\/p>\n
The narrowing of the CON-LAB lead is mostly due to the rise in the Labour vote.\u00a0 The Conservatives have lost votes over the last 2 weeks but they are still at a higher level than they were before the election was called and 43.7% would still be higher than\u00a0Thatcher’s landslides in 1983 & 1987.\u00a0 It is the 12pt rise in the Labour vote that has changed everything.\u00a0 Whilst in\u00a0the last 2 weeks about 3% of Conservatives have switched to Labour, the other 9% has come from the Greens, Liberal Democrats, UKIP and Nationalists.\u00a0 So this raises the question, is the Labour recovery due to pro-Labour enthusiasm or an anti-Tory tactical vote?\u00a0 We will find out on June 8th.<\/p>\n
In the meantime, let me take you through\u00a0the\u00a05 steps to clearing up the confusion.<\/p>\n
Step 1 – Divide the pollsters into 2 groups based on their TURNOUT methodology<\/strong><\/span><\/h3>\nThe pollsters need to be split as follows.<\/p>\n
\n- MODELLER<\/strong> group includes ICM, Comres and TNS.<\/li>\n
- SELF REPORT<\/strong> group which includes everyone else.<\/li>\n<\/ul>\n
If you do this and calculate the average CON-LAB lead across all polls published by the two groups and do this for 6 different time periods, a clear pattern emerges as shown in the chart below.<\/p>\n
![\"\"](\"https:\/\/marriott-stats.com\/nigels-blog\/wp-content\/uploads\/2017\/06\/PollEffect-TurnoutEff-300x190.png\")
<\/p>\n
The manifestos were published just before the Manchester bombing and the effects appeared in the polls afterwards.\u00a0 The labels show the average GB vote shares for the Conservatives (C) and Labour (L).<\/p>\n
This chart clarifies many things straightaway.\u00a0 Depending on how you are estimating turnout, you will either be saying that the CON-LAB lead has fallen from 7.4% to\u00a05.4% and is now lower than the 6.5% lead the Conservatives had in the 2015 election\u00a0OR you will be saying that the CON-LAB lead is still 11.5% and 5pts better than 2015 for the Conservatives.\u00a0\u00a0 Whilst the gap between the two methods has widened in the last few days, there has been a persistent gap since the start of the year.\u00a0 Before the election, the Self-Reports had the lead 2pts lower than the Modellers but once the election was called, the gap widened to 4pts and then 6pts in the last few days.<\/p>\n
Step 2 – Decide who has the better turnout model,\u00a0Modellers or Self-Reporters?<\/strong><\/span><\/h3>\nWhy are the two groups so different?\u00a0 The answer is that turnout modelling takes into account two factors<\/a> and your estimated turnout will depend on how much weight you are giving to each.<\/p>\n\n- The intention to vote as expressed by the survey respondents.<\/li>\n
- The historical turnout among different demographic groups.<\/li>\n<\/ol>\n
The Modellers are placing much greater weight on historical turnout among various demographics.\u00a0 By far and away the most important is age as the chart below\u00a0shows.\u00a0 You will note that young people are much less likely to vote and historically this group is much more likely to vote Labour.\u00a0 Note that the author of this chart stated later that the 2016 turnout for 18-24 was incorrect and should have been 47%.<\/p>\n
![\"\"](\"https:\/\/marriott-stats.com\/nigels-blog\/wp-content\/uploads\/2017\/06\/PolEffect-Turnout-300x187.jpg\")
<\/p>\n
By contrast, the Self-Reporters give greater weight to what survey respondents say about their likelihood to\u00a0vote.\u00a0 I have seen analysis by some analysts that claim the implied turnout among 18-24 year olds among Self-Reporters is over 60% which is much higher than the 47% seen in the referendum.\u00a0 There is no question that the widening gap between Self Reporters and Modellers is due to younger voters (especially women)\u00a0apparently becoming more enthusiastic about voting<\/a> and with their pro-Labour bias it is no surprise that self-reporters have seen a rapidly narrowing CON-LAB lead.\u00a0 By contrast, Modellers who place much greater weight on historical turnout see little change over the last few days.<\/p>\nSo who will be more correct on Thursday?\u00a0 I have heard a lot of talk about this being a key election for young voters “to stop their future being stolen”.\u00a0 But tweets and social media posts are far too easy to mistake for genuine enthusiasm and history is a powerful force to overcome.\u00a0 The following points make me sceptical about the supposed enthusiasm of young voters.<\/p>\n
\n- Nearly all pollsters have now switched to online panels.\u00a0 Only Ipsos Mori & Survation are still carrying out phone polls.\u00a0 Online panels correctly predicted a Leave vote in 2016 whereas phone polls predicted a Remain vote.\u00a0 But online panels always run the risk of recruiting techphiles and missing techphobes and the young are certainly more likely to be the former.\u00a0 The second risk is the ease of recruiting politically engaged voters who again tend to be more pro-Labour and this was ultimately blamed for the polling error of 2015 by the British Polling Council<\/a>.\u00a0 Finally, getting the referendum right doesn’t mean you will get the general election right and I have demonstrated that the demographics of the Leave vote bore almost no relation to\u00a0the\u00a0demographics\u00a0of the 2015 election<\/a>.<\/li>\n
- In 2014, Scotland recorded their highest ever turnout of 85% in their Independence referendum which was a 21% increase on the 2010 general election turnout of 64%.\u00a0 In 2015, Scottish was completely shaken up and realigned with the SNP taking 50% of the vote (up 30% on 2010) and all but wiping out Labour who had dominated Scottish politics for decades.\u00a0 It was a complete realignment of Scottish politics where again it was said that “No voters had stolen the future of the young” in the aftermath and the realignment represented an enthusiasm among Yes voters to change things.\u00a0 Does this sound familiar?\u00a0 So what happened to turnout in 2015?\u00a0 It fell from 85% to 71%, which equated to 2\/3 of the additional voters in 2014 not\u00a0bothering to vote in 2015 despite all the enthusiasm and incentive to do so since the polls were forecasting a hung parliament in 2015 giving the SNP an opportunity to play kingmaker.\u00a0 This is a real data point to take into account.<\/li>\n
- Converting young votes into seats is going to harder than Labour thinks.\u00a0 The polls are showing that Labour are closing the gap best in major cities and the South but these are the wrong places to pick these votes.\u00a0 For a start, seats with a large proportion of young voters tend to be Labour in any case.\u00a0 For example\u00a0in 2015, the Tories only had 11 of the top 67 seats where students outnumber retired people in England & Wales.\u00a0 Such seats are often university towns.\u00a0 In the South, Labour is a long way behind the Conservatives and whilst they are closing the gap, it is not yet enough to significantly hurt the Conservatives.\u00a0 If Labour want to inflict damage on the Conservatives, they need to protect their seats in the North and make gains in the Midlands and they are not doing this.<\/li>\n<\/ul>\n
Saying all that, Modellers will get it wrong if this election turns out to be a game changer.\u00a0 I have already explored the likelihood of 2017 being a realignment election <\/a>and I concluded that the answer was yes but the realignment would favour the Conservatives, such as them becoming the party of the working class.\u00a0 If something like that could happen then there is nothing to stop young voters increasing their turnout as well in which case Self Reporters will be more likely to get it right.<\/p>\nI have decided to use the Scottish data point I referred to as a way of deciding between the two methods.\u00a0\u00a0I am taking a weighted average of the Modellers CON-LAB lead of 11.5% (2\/3 weight) and the Self-Report CON-LAB lead of 5.5% (1\/3) weight which gives an expected CON-LAB lead of 9.5%, 3% higher than the current combined average CON-LAB lead of all polls which is 6.5% (the same as 2015).\u00a0 In effect, I have decided that the Modellers are\u00a0assuming unchanged turnout of 66% in 2017\u00a0and the Self-Reports are assuming a turnout equal to the referendum of 72%.\u00a0 My weighted average implies an expected turnout of 68%.\u00a0 This estimate replicates the changes seen in Scotland where a 21% increase in turnout\u00a0from 2010\u00a0to 2014\u00a0was followed by a 14% fall in turnout in 2015 i.e. 2015 turnout was 2\/3 of 2014 plus 1\/3 of 2010.<\/p>\n
In doing this and arriving at a CON-LAB lead estimate 3% higher than the polls, I have effectively assumed that the poll average will be in error by 3%.\u00a0 This is very close to the long run 2.6% underestimate in the CON-LAB lead I identified from analysing polling errors from 1945 to 2015<\/a>.\u00a0 The nature of the error though is different this time.\u00a0 In 2015, all pollsters got it wrong but in 2017 I am saying some will get it right.\u00a0 Of course there is nothing to stop there being additional polling error on both sides of the turnout debate on top of what I have been describing here.<\/p>\nStep 3 –\u00a0Decide if you can use Uniform National Swing (UNS) to predict seats.<\/strong><\/span><\/h3>\nOnce you have decided on your turnout model, this will give you your projected CON-LAB lead.\u00a0 Suppose we assume that Self Reporters are right and the CON-LAB lead will be 5.5% in Great Britain in 2017.\u00a0 This would be 1% lower than the CON-LAB lead of 6.5% in 2015.\u00a0 How many seats would this cost the Conservatives?<\/p>\n
Uniform National Swing (UNS) is a method that assumes that if the CON-LAB changes by 1% at a national level, on average the CON-LAB lead in every seat will also change by 1%.\u00a0 So any seat with a Conservative majority of less than 1% will be lost in such a scenario.\u00a0 How many seats are there?\u00a0 The answer is 6 listed below.<\/p>\n
\n- Croydon Central (London)<\/li>\n
- Derby North (East Midlands)<\/li>\n
- Gower (Wales)<\/li>\n
- Vale of Clwyd (Wales)<\/li>\n
- Bury North (North West)<\/li>\n
- Morley & Outwood (Yorkshire), Ed Balls former seat.<\/li>\n<\/ul>\n
You will notice only one of these seats is in the South, Croydon Central.\u00a0 I stated earlier that Labour is doing better in major cities and the South than in the Midlands and North and I based this on chart R1 of my opinion poll tracker<\/a>.\u00a0 This chart is based on the latest polls (both Self Reporters and Modellers) and predicts a CON-LAB lead nationally of 6.5%, exactly the same as 2015.<\/p>\n![\"\"](\"https:\/\/marriott-stats.com\/nigels-blog\/wp-content\/uploads\/2017\/06\/PollEffect-R1-170603-300x150.png\")
<\/p>\n
In the Midlands, North & Wales, far from closing the gap on the Conservatives, Labour are losing ground.\u00a0 Yes they are gaining votes in these areas but the Conservatives are gaining even more with the result that either the CON-LAB lead is getting larger (Midlands)\u00a0or the LAB-CON lead is getting smaller (North & Wales).\u00a0\u00a0 In London and the South,\u00a0Labour are making larger gains\u00a0than the Conservatives\u00a0and are\u00a0narrowing the gap by 5% or so.\u00a0\u00a0But the Conservatives have very few seats in the South with such majorities and the list below is all that\u00a0Labour would\u00a0gain in London and the South based on the\u00a0changes shown in R1.<\/p>\n
\n- Croydon Central (London)<\/li>\n
- Brighton Kemptown (South East)<\/li>\n
- Southampton Itchen (South East)<\/li>\n
- Thurrock (East)<\/li>\n
- Bedford (East)<\/li>\n
- Plymouth Moor View (South West)<\/li>\n
- Plymouth Sutton & Devonport (South West)<\/li>\n<\/ul>\n
At the same time,\u00a0Labour would fail to take the other 5 seats I listed before in the North, Wales & Midlands and instead\u00a0the Conservatives would make the following 7 gains based on chart R1 which would cancel out these 7 losses.<\/p>\n
\n- NE Derbyshire (East Midlands)<\/li>\n
- Halifax (Yorkshire)<\/li>\n
- Dewsbury (Yorskshire)<\/li>\n
- Chester (North West)<\/li>\n
- Wirral West (North West)<\/li>\n
- Barrow & Furness (North West)<\/li>\n
- Lancaster & Fleetwood (North West)<\/li>\n<\/ul>\n
Then there is Scotland.\u00a0 Chart R1 shows a dramatic change around with the Nationalists down nearly 10% and the Conservatives up 15% and in second place.\u00a0 They are well set to win 5 to 10 seats and my forecast\u00a0was 8.<\/p>\n
So to summarise.\u00a0 Uniform National Swing is not a valid model as shown by the changes in chart R1.\u00a0 More than that, R1 predicts at a national level that the CON-LAB lead will be unchanged but the regional redistribution of votes means that the Conservatives will make a net gain of 8 seats.\u00a0 So an unchanged CON-LAB lead increases the number of seats for the Conservatives which raises the question, what does the CON-LAB lead need to be for them to lose seats and their majority?\u00a0 The answer is to abandon Uniform National Swing and to use a non-Uniform Regional Swing model instead.<\/p>\n
Step 4 – Take into account the variation in the Leave vote around the country<\/strong><\/span><\/h3>\nIf you have been following my General Election forec<\/a>asts, you should be familiar with my nURS model which is one of two models I now use to make my 2017 predictions<\/a>.\u00a0 Non-Uniform Regional Swing starts by working out the votes in each seat based on the changes shown in chart R1 and then adjusting the Conservative vote based on the extent to which the seat was above or below the regional average for their Leave vote share in 2016.\u00a0 Above average Leave areas see higher Conservative votes, below average Leave areas see lower Conservative votes.<\/p>\nIf you are familiar with the referendum results of 2016, you may have already spotted this pattern in chart R1.\u00a0 In London (which voted Remain) and the South (which narrowly voted Leave), Labour is closing the CON-LAB gap.\u00a0 Elsewhere in England & Wales where the Leave vote was strong, the Conservatives are either extending their lead over Labour or closing the gap on Labour.\u00a0 Scotland has to be ignored here as the political debate is influenced by the Unionist\/Natioanlist divide in addition to Brexit.<\/p>\n
This pattern is shown better in the scatter plot.\u00a0 Along the horizontal axis, I have plotted each region’s Leave vote share as a differential from the nat![\"\"](\"https:\/\/marriott-stats.com\/nigels-blog\/wp-content\/uploads\/2017\/06\/PollEffect-CONLVeff2-300x254.png\")
ional average of 52%.\u00a0 So London which voted 40% Leave has a differential of -12% and the South East where just under 52% voted Leave has a differential of effectively zero.\u00a0 On the vertical axis, I have plotted the expected change in the CON-LAB lead in each region from 2015 to 2017 based on the latest polls in chart R1.\u00a0 Fitting the blue solid line\u00a0gives the equation of this fit in the blue label.<\/p>\n
This is a not a very good statistical fit but it is still informative.\u00a0 The blue label says that there is a CON-LAB\u00a0lead to Leave vote ELASTICITY of +0.4 i.e. for every 1% increase in the Leave vote, the CON-LAB lead increase by 0.4%.\u00a0 However, London is quite an outlier in England and would called a “high leverage” point in statistical terms, i.e. the parameters of the model as shown by the blue label are highly sensitive to any errors in the London estimate.\u00a0 I have in fact realised that in the past, my regional crossbreak analysis had a bias that overstated the CON-LAB lead in London which I have now corrected but I may still be getting it wrong.<\/p>\n
If I exclude London and recalculate the fit for regions in England & Wales outside of London, the elasticity increases to +0.62 and the fit is shown by the dashed green line.\u00a0 Again this fit is not great but bear in mind that the CON-LAB leads for all regions are simply estimates based on the polls and thus subject to error.\u00a0 However, +0.62 provides independent c![\"\"](\"https:\/\/marriott-stats.com\/nigels-blog\/wp-content\/uploads\/2017\/06\/PollEffect-CONLVeff1-300x260.png\")
onfirmation in my mind of the mathematical basis of my nURS model as shown in the next scatter plot.\u00a0 That model uses a CON to Leave vote elasticity of +0.7 which is close enough to +0.62 to decide that my elasticity is basically on the right lines.\u00a0 The second scatter plot is based on the 5 sub regions of Wales (represented by red diamonds)\u00a0from 3 Welsh Barometer polls<\/a>\u00a0plus constituency level polls in 5 strong Remain seats (Brighton Pavilion, Bath<\/a>, Edinburgh South<\/a>, Battersea and Kensington<\/a>) which are represented by\u00a0blue and white diamonds.<\/p>\nHaving two independent analyses ending up with\u00a0similar results gives me confidence that I have a way to measure the non-uniformality of the CON-LAB lead in each seat based on the Leave vote.\u00a0 If a seat’s Leave vote\u00a0is higher than 52%, then\u00a0for every additional\u00a010pts in the Leave vote, the CON-LAB lead will\u00a0be 7pts higher\u00a0than the CON-LAB lead\u00a0shown by the polls in\u00a0chart R1.\u00a0 Conversely if a seat’s\u00a0Remain vote is lower than 48%, then for every additional 10pts\u00a0in the Remain vote, the CON-LAB lead will be 7pts lower than the\u00a0lead shown in the polls by chart R1.\u00a0 I can now use my nURS model to answer the question of at what level will the Conservatives lose their majority?<\/p>\n
Step 5 – Identify the CON-LAB lead threshold for a working majority.<\/strong><\/span><\/h3>\nToday, the Conservatives hold 330 seats out of 650 seats which works out as a majority of 10 seats.\u00a0 At first sight, it would seem that if they lost 5 seats and ended up on 325 seats, they would lose their majority but this is not correct.\u00a0 For a start, the Speaker is elected as an independent even though he was formerly a member of the Conservative party and is not counted in the 330 seats.\u00a0 In addition, the speaker does not have a vote so if the Conservatives ended up with 325 seats, they would have a working majority of 1 seat.<\/p>\n
In fact the working majority threshold is\u00a0323 seats due to the fact that the 4 Sinn Fein MPs do not take their seats in the House of Commons <\/a>and as such do not vote.\u00a0 Out of 650 MPs, only 645 actually vote which is why the working majority threshold is 323 seats.\u00a0 This means the Conservatives need to lose 8 seats to lose their![\"\"](\"https:\/\/marriott-stats.com\/nigels-blog\/wp-content\/uploads\/2017\/06\/PollEffect-nURSleadEff-300x212.png\")
working majority.\u00a0 I showed in step 3 that the Conservatives can expect to gain seats even if the national CON-LAB lead remains unchanged at 6.5% due to the way the votes are being redistributed unevenly by region.\u00a0 I will now use my nURS model described in step 4 to generate an election forecast for a variety of CON-LAB leads shown in the blue and green labels in table P0.<\/p>\nThe first two CON-LAB leads represent the 2 groups of pollsters, Self Reporters (5.4%) and Modellers (11.5%).\u00a0 Even if the Self-Reporters were correct, the Conservatives would gain 11 seats using nURS which would mostly come from Scotland.\u00a0 However I am sure Theresa May would be very unhappy to have only increased her working majority by 22 seats and that she is really hoping that the Modellers are right where the Tories\u00a0gain 52 seats and a 119 seat working majority.<\/p>\n
The 6.6% group represents the average of all polls today and equates to an unchanged CON-LAB lead from 2015.\u00a0 Unlike what I said in step 3 where I showed under uniform regional swing in this scenario, the Conservatives would make a net gain of 8 seats, under non-Uniform Regional Swing, they would gain a further 10 seats.\u00a0 This is the impact of Brexit becoming the main factor of the election.\u00a0 Leave seats outnumber Remain seats by 8 to 5 and this increases the Conservatives gains.<\/p>\n
To eliminate the Tories working majority, Labour has to get the CON-LAB lead down to 3.5% which is 3% lower than 2015.\u00a0 This is 4th line in the chart I showed at the beginning of the post (repeated below)\u00a0and appears as a solid brown line.<\/p>\n
<\/p>\n
The 5th and final forecast in table P0 is for my assumed CON-LAB lead based on 2:1 weighted average of the Modellers and Self-Reporters as described in step 2.\u00a0 So my official nURS forecast is\u00a0for a working majority of 89 seats.\u00a0 Bear in mind that my official election forecast is\u00a0the average of my nURS forecast and my Brexit Realignment model <\/a>(EU16R)\u00a0and in the past, EU16R has tended to give higher majorities than nURS so it is quite likely that I will still be predicting a 100+ seat majority when I publish my final forecast on Tuesday.<\/p>\nTable P0 shows you how the number of Conservative seats is related to the CON-LAB lead and the resulting elasticity is 7.2 seats per % point.\u00a0 So if you see a poll tomorrow saying that Conservatives have an 8.5% lead over Labour, you can start with 322 seats (the threshold for a working majority)\u00a0and a CON-LAB lead of\u00a03.5%, subtract that from 8.5% to get 5pts and multiply that by 7.2 to get an additional 36 seats.\u00a0 This means the Conservatives can be expected to have 322+36=358 seats in this instance.<\/p>\n
If you do this and calculate the average CON-LAB lead across all polls published by the two groups and do this for 6 different time periods, a clear pattern emerges as shown in the chart below.<\/p>\n
<\/p>\n
The manifestos were published just before the Manchester bombing and the effects appeared in the polls afterwards.\u00a0 The labels show the average GB vote shares for the Conservatives (C) and Labour (L).<\/p>\n
This chart clarifies many things straightaway.\u00a0 Depending on how you are estimating turnout, you will either be saying that the CON-LAB lead has fallen from 7.4% to\u00a05.4% and is now lower than the 6.5% lead the Conservatives had in the 2015 election\u00a0OR you will be saying that the CON-LAB lead is still 11.5% and 5pts better than 2015 for the Conservatives.\u00a0\u00a0 Whilst the gap between the two methods has widened in the last few days, there has been a persistent gap since the start of the year.\u00a0 Before the election, the Self-Reports had the lead 2pts lower than the Modellers but once the election was called, the gap widened to 4pts and then 6pts in the last few days.<\/p>\n
Step 2 – Decide who has the better turnout model,\u00a0Modellers or Self-Reporters?<\/strong><\/span><\/h3>\nWhy are the two groups so different?\u00a0 The answer is that turnout modelling takes into account two factors<\/a> and your estimated turnout will depend on how much weight you are giving to each.<\/p>\n\n- The intention to vote as expressed by the survey respondents.<\/li>\n
- The historical turnout among different demographic groups.<\/li>\n<\/ol>\n
The Modellers are placing much greater weight on historical turnout among various demographics.\u00a0 By far and away the most important is age as the chart below\u00a0shows.\u00a0 You will note that young people are much less likely to vote and historically this group is much more likely to vote Labour.\u00a0 Note that the author of this chart stated later that the 2016 turnout for 18-24 was incorrect and should have been 47%.<\/p>\n
<\/p>\n
By contrast, the Self-Reporters give greater weight to what survey respondents say about their likelihood to\u00a0vote.\u00a0 I have seen analysis by some analysts that claim the implied turnout among 18-24 year olds among Self-Reporters is over 60% which is much higher than the 47% seen in the referendum.\u00a0 There is no question that the widening gap between Self Reporters and Modellers is due to younger voters (especially women)\u00a0apparently becoming more enthusiastic about voting<\/a> and with their pro-Labour bias it is no surprise that self-reporters have seen a rapidly narrowing CON-LAB lead.\u00a0 By contrast, Modellers who place much greater weight on historical turnout see little change over the last few days.<\/p>\nSo who will be more correct on Thursday?\u00a0 I have heard a lot of talk about this being a key election for young voters “to stop their future being stolen”.\u00a0 But tweets and social media posts are far too easy to mistake for genuine enthusiasm and history is a powerful force to overcome.\u00a0 The following points make me sceptical about the supposed enthusiasm of young voters.<\/p>\n
\n- Nearly all pollsters have now switched to online panels.\u00a0 Only Ipsos Mori & Survation are still carrying out phone polls.\u00a0 Online panels correctly predicted a Leave vote in 2016 whereas phone polls predicted a Remain vote.\u00a0 But online panels always run the risk of recruiting techphiles and missing techphobes and the young are certainly more likely to be the former.\u00a0 The second risk is the ease of recruiting politically engaged voters who again tend to be more pro-Labour and this was ultimately blamed for the polling error of 2015 by the British Polling Council<\/a>.\u00a0 Finally, getting the referendum right doesn’t mean you will get the general election right and I have demonstrated that the demographics of the Leave vote bore almost no relation to\u00a0the\u00a0demographics\u00a0of the 2015 election<\/a>.<\/li>\n
- In 2014, Scotland recorded their highest ever turnout of 85% in their Independence referendum which was a 21% increase on the 2010 general election turnout of 64%.\u00a0 In 2015, Scottish was completely shaken up and realigned with the SNP taking 50% of the vote (up 30% on 2010) and all but wiping out Labour who had dominated Scottish politics for decades.\u00a0 It was a complete realignment of Scottish politics where again it was said that “No voters had stolen the future of the young” in the aftermath and the realignment represented an enthusiasm among Yes voters to change things.\u00a0 Does this sound familiar?\u00a0 So what happened to turnout in 2015?\u00a0 It fell from 85% to 71%, which equated to 2\/3 of the additional voters in 2014 not\u00a0bothering to vote in 2015 despite all the enthusiasm and incentive to do so since the polls were forecasting a hung parliament in 2015 giving the SNP an opportunity to play kingmaker.\u00a0 This is a real data point to take into account.<\/li>\n
- Converting young votes into seats is going to harder than Labour thinks.\u00a0 The polls are showing that Labour are closing the gap best in major cities and the South but these are the wrong places to pick these votes.\u00a0 For a start, seats with a large proportion of young voters tend to be Labour in any case.\u00a0 For example\u00a0in 2015, the Tories only had 11 of the top 67 seats where students outnumber retired people in England & Wales.\u00a0 Such seats are often university towns.\u00a0 In the South, Labour is a long way behind the Conservatives and whilst they are closing the gap, it is not yet enough to significantly hurt the Conservatives.\u00a0 If Labour want to inflict damage on the Conservatives, they need to protect their seats in the North and make gains in the Midlands and they are not doing this.<\/li>\n<\/ul>\n
Saying all that, Modellers will get it wrong if this election turns out to be a game changer.\u00a0 I have already explored the likelihood of 2017 being a realignment election <\/a>and I concluded that the answer was yes but the realignment would favour the Conservatives, such as them becoming the party of the working class.\u00a0 If something like that could happen then there is nothing to stop young voters increasing their turnout as well in which case Self Reporters will be more likely to get it right.<\/p>\nI have decided to use the Scottish data point I referred to as a way of deciding between the two methods.\u00a0\u00a0I am taking a weighted average of the Modellers CON-LAB lead of 11.5% (2\/3 weight) and the Self-Report CON-LAB lead of 5.5% (1\/3) weight which gives an expected CON-LAB lead of 9.5%, 3% higher than the current combined average CON-LAB lead of all polls which is 6.5% (the same as 2015).\u00a0 In effect, I have decided that the Modellers are\u00a0assuming unchanged turnout of 66% in 2017\u00a0and the Self-Reports are assuming a turnout equal to the referendum of 72%.\u00a0 My weighted average implies an expected turnout of 68%.\u00a0 This estimate replicates the changes seen in Scotland where a 21% increase in turnout\u00a0from 2010\u00a0to 2014\u00a0was followed by a 14% fall in turnout in 2015 i.e. 2015 turnout was 2\/3 of 2014 plus 1\/3 of 2010.<\/p>\n
In doing this and arriving at a CON-LAB lead estimate 3% higher than the polls, I have effectively assumed that the poll average will be in error by 3%.\u00a0 This is very close to the long run 2.6% underestimate in the CON-LAB lead I identified from analysing polling errors from 1945 to 2015<\/a>.\u00a0 The nature of the error though is different this time.\u00a0 In 2015, all pollsters got it wrong but in 2017 I am saying some will get it right.\u00a0 Of course there is nothing to stop there being additional polling error on both sides of the turnout debate on top of what I have been describing here.<\/p>\nStep 3 –\u00a0Decide if you can use Uniform National Swing (UNS) to predict seats.<\/strong><\/span><\/h3>\nOnce you have decided on your turnout model, this will give you your projected CON-LAB lead.\u00a0 Suppose we assume that Self Reporters are right and the CON-LAB lead will be 5.5% in Great Britain in 2017.\u00a0 This would be 1% lower than the CON-LAB lead of 6.5% in 2015.\u00a0 How many seats would this cost the Conservatives?<\/p>\n
Uniform National Swing (UNS) is a method that assumes that if the CON-LAB changes by 1% at a national level, on average the CON-LAB lead in every seat will also change by 1%.\u00a0 So any seat with a Conservative majority of less than 1% will be lost in such a scenario.\u00a0 How many seats are there?\u00a0 The answer is 6 listed below.<\/p>\n
\n- Croydon Central (London)<\/li>\n
- Derby North (East Midlands)<\/li>\n
- Gower (Wales)<\/li>\n
- Vale of Clwyd (Wales)<\/li>\n
- Bury North (North West)<\/li>\n
- Morley & Outwood (Yorkshire), Ed Balls former seat.<\/li>\n<\/ul>\n
You will notice only one of these seats is in the South, Croydon Central.\u00a0 I stated earlier that Labour is doing better in major cities and the South than in the Midlands and North and I based this on chart R1 of my opinion poll tracker<\/a>.\u00a0 This chart is based on the latest polls (both Self Reporters and Modellers) and predicts a CON-LAB lead nationally of 6.5%, exactly the same as 2015.<\/p>\n<\/p>\n
In the Midlands, North & Wales, far from closing the gap on the Conservatives, Labour are losing ground.\u00a0 Yes they are gaining votes in these areas but the Conservatives are gaining even more with the result that either the CON-LAB lead is getting larger (Midlands)\u00a0or the LAB-CON lead is getting smaller (North & Wales).\u00a0\u00a0 In London and the South,\u00a0Labour are making larger gains\u00a0than the Conservatives\u00a0and are\u00a0narrowing the gap by 5% or so.\u00a0\u00a0But the Conservatives have very few seats in the South with such majorities and the list below is all that\u00a0Labour would\u00a0gain in London and the South based on the\u00a0changes shown in R1.<\/p>\n
\n- Croydon Central (London)<\/li>\n
- Brighton Kemptown (South East)<\/li>\n
- Southampton Itchen (South East)<\/li>\n
- Thurrock (East)<\/li>\n
- Bedford (East)<\/li>\n
- Plymouth Moor View (South West)<\/li>\n
- Plymouth Sutton & Devonport (South West)<\/li>\n<\/ul>\n
At the same time,\u00a0Labour would fail to take the other 5 seats I listed before in the North, Wales & Midlands and instead\u00a0the Conservatives would make the following 7 gains based on chart R1 which would cancel out these 7 losses.<\/p>\n
\n- NE Derbyshire (East Midlands)<\/li>\n
- Halifax (Yorkshire)<\/li>\n
- Dewsbury (Yorskshire)<\/li>\n
- Chester (North West)<\/li>\n
- Wirral West (North West)<\/li>\n
- Barrow & Furness (North West)<\/li>\n
- Lancaster & Fleetwood (North West)<\/li>\n<\/ul>\n
Then there is Scotland.\u00a0 Chart R1 shows a dramatic change around with the Nationalists down nearly 10% and the Conservatives up 15% and in second place.\u00a0 They are well set to win 5 to 10 seats and my forecast\u00a0was 8.<\/p>\n
So to summarise.\u00a0 Uniform National Swing is not a valid model as shown by the changes in chart R1.\u00a0 More than that, R1 predicts at a national level that the CON-LAB lead will be unchanged but the regional redistribution of votes means that the Conservatives will make a net gain of 8 seats.\u00a0 So an unchanged CON-LAB lead increases the number of seats for the Conservatives which raises the question, what does the CON-LAB lead need to be for them to lose seats and their majority?\u00a0 The answer is to abandon Uniform National Swing and to use a non-Uniform Regional Swing model instead.<\/p>\n
Step 4 – Take into account the variation in the Leave vote around the country<\/strong><\/span><\/h3>\nIf you have been following my General Election forec<\/a>asts, you should be familiar with my nURS model which is one of two models I now use to make my 2017 predictions<\/a>.\u00a0 Non-Uniform Regional Swing starts by working out the votes in each seat based on the changes shown in chart R1 and then adjusting the Conservative vote based on the extent to which the seat was above or below the regional average for their Leave vote share in 2016.\u00a0 Above average Leave areas see higher Conservative votes, below average Leave areas see lower Conservative votes.<\/p>\nIf you are familiar with the referendum results of 2016, you may have already spotted this pattern in chart R1.\u00a0 In London (which voted Remain) and the South (which narrowly voted Leave), Labour is closing the CON-LAB gap.\u00a0 Elsewhere in England & Wales where the Leave vote was strong, the Conservatives are either extending their lead over Labour or closing the gap on Labour.\u00a0 Scotland has to be ignored here as the political debate is influenced by the Unionist\/Natioanlist divide in addition to Brexit.<\/p>\n
This pattern is shown better in the scatter plot.\u00a0 Along the horizontal axis, I have plotted each region’s Leave vote share as a differential from the national average of 52%.\u00a0 So London which voted 40% Leave has a differential of -12% and the South East where just under 52% voted Leave has a differential of effectively zero.\u00a0 On the vertical axis, I have plotted the expected change in the CON-LAB lead in each region from 2015 to 2017 based on the latest polls in chart R1.\u00a0 Fitting the blue solid line\u00a0gives the equation of this fit in the blue label.<\/p>\n
This is a not a very good statistical fit but it is still informative.\u00a0 The blue label says that there is a CON-LAB\u00a0lead to Leave vote ELASTICITY of +0.4 i.e. for every 1% increase in the Leave vote, the CON-LAB lead increase by 0.4%.\u00a0 However, London is quite an outlier in England and would called a “high leverage” point in statistical terms, i.e. the parameters of the model as shown by the blue label are highly sensitive to any errors in the London estimate.\u00a0 I have in fact realised that in the past, my regional crossbreak analysis had a bias that overstated the CON-LAB lead in London which I have now corrected but I may still be getting it wrong.<\/p>\n
If I exclude London and recalculate the fit for regions in England & Wales outside of London, the elasticity increases to +0.62 and the fit is shown by the dashed green line.\u00a0 Again this fit is not great but bear in mind that the CON-LAB leads for all regions are simply estimates based on the polls and thus subject to error.\u00a0 However, +0.62 provides independent confirmation in my mind of the mathematical basis of my nURS model as shown in the next scatter plot.\u00a0 That model uses a CON to Leave vote elasticity of +0.7 which is close enough to +0.62 to decide that my elasticity is basically on the right lines.\u00a0 The second scatter plot is based on the 5 sub regions of Wales (represented by red diamonds)\u00a0from 3 Welsh Barometer polls<\/a>\u00a0plus constituency level polls in 5 strong Remain seats (Brighton Pavilion, Bath<\/a>, Edinburgh South<\/a>, Battersea and Kensington<\/a>) which are represented by\u00a0blue and white diamonds.<\/p>\nHaving two independent analyses ending up with\u00a0similar results gives me confidence that I have a way to measure the non-uniformality of the CON-LAB lead in each seat based on the Leave vote.\u00a0 If a seat’s Leave vote\u00a0is higher than 52%, then\u00a0for every additional\u00a010pts in the Leave vote, the CON-LAB lead will\u00a0be 7pts higher\u00a0than the CON-LAB lead\u00a0shown by the polls in\u00a0chart R1.\u00a0 Conversely if a seat’s\u00a0Remain vote is lower than 48%, then for every additional 10pts\u00a0in the Remain vote, the CON-LAB lead will be 7pts lower than the\u00a0lead shown in the polls by chart R1.\u00a0 I can now use my nURS model to answer the question of at what level will the Conservatives lose their majority?<\/p>\n
Step 5 – Identify the CON-LAB lead threshold for a working majority.<\/strong><\/span><\/h3>\nToday, the Conservatives hold 330 seats out of 650 seats which works out as a majority of 10 seats.\u00a0 At first sight, it would seem that if they lost 5 seats and ended up on 325 seats, they would lose their majority but this is not correct.\u00a0 For a start, the Speaker is elected as an independent even though he was formerly a member of the Conservative party and is not counted in the 330 seats.\u00a0 In addition, the speaker does not have a vote so if the Conservatives ended up with 325 seats, they would have a working majority of 1 seat.<\/p>\n
In fact the working majority threshold is\u00a0323 seats due to the fact that the 4 Sinn Fein MPs do not take their seats in the House of Commons <\/a>and as such do not vote.\u00a0 Out of 650 MPs, only 645 actually vote which is why the working majority threshold is 323 seats.\u00a0 This means the Conservatives need to lose 8 seats to lose their working majority.\u00a0 I showed in step 3 that the Conservatives can expect to gain seats even if the national CON-LAB lead remains unchanged at 6.5% due to the way the votes are being redistributed unevenly by region.\u00a0 I will now use my nURS model described in step 4 to generate an election forecast for a variety of CON-LAB leads shown in the blue and green labels in table P0.<\/p>\nThe first two CON-LAB leads represent the 2 groups of pollsters, Self Reporters (5.4%) and Modellers (11.5%).\u00a0 Even if the Self-Reporters were correct, the Conservatives would gain 11 seats using nURS which would mostly come from Scotland.\u00a0 However I am sure Theresa May would be very unhappy to have only increased her working majority by 22 seats and that she is really hoping that the Modellers are right where the Tories\u00a0gain 52 seats and a 119 seat working majority.<\/p>\n
The 6.6% group represents the average of all polls today and equates to an unchanged CON-LAB lead from 2015.\u00a0 Unlike what I said in step 3 where I showed under uniform regional swing in this scenario, the Conservatives would make a net gain of 8 seats, under non-Uniform Regional Swing, they would gain a further 10 seats.\u00a0 This is the impact of Brexit becoming the main factor of the election.\u00a0 Leave seats outnumber Remain seats by 8 to 5 and this increases the Conservatives gains.<\/p>\n
To eliminate the Tories working majority, Labour has to get the CON-LAB lead down to 3.5% which is 3% lower than 2015.\u00a0 This is 4th line in the chart I showed at the beginning of the post (repeated below)\u00a0and appears as a solid brown line.<\/p>\n
<\/p>\n
The 5th and final forecast in table P0 is for my assumed CON-LAB lead based on 2:1 weighted average of the Modellers and Self-Reporters as described in step 2.\u00a0 So my official nURS forecast is\u00a0for a working majority of 89 seats.\u00a0 Bear in mind that my official election forecast is\u00a0the average of my nURS forecast and my Brexit Realignment model <\/a>(EU16R)\u00a0and in the past, EU16R has tended to give higher majorities than nURS so it is quite likely that I will still be predicting a 100+ seat majority when I publish my final forecast on Tuesday.<\/p>\nTable P0 shows you how the number of Conservative seats is related to the CON-LAB lead and the resulting elasticity is 7.2 seats per % point.\u00a0 So if you see a poll tomorrow saying that Conservatives have an 8.5% lead over Labour, you can start with 322 seats (the threshold for a working majority)\u00a0and a CON-LAB lead of\u00a03.5%, subtract that from 8.5% to get 5pts and multiply that by 7.2 to get an additional 36 seats.\u00a0 This means the Conservatives can be expected to have 322+36=358 seats in this instance.<\/p>\n
- \n
- The intention to vote as expressed by the survey respondents.<\/li>\n
- The historical turnout among different demographic groups.<\/li>\n<\/ol>\n
The Modellers are placing much greater weight on historical turnout among various demographics.\u00a0 By far and away the most important is age as the chart below\u00a0shows.\u00a0 You will note that young people are much less likely to vote and historically this group is much more likely to vote Labour.\u00a0 Note that the author of this chart stated later that the 2016 turnout for 18-24 was incorrect and should have been 47%.<\/p>\n
<\/p>\nBy contrast, the Self-Reporters give greater weight to what survey respondents say about their likelihood to\u00a0vote.\u00a0 I have seen analysis by some analysts that claim the implied turnout among 18-24 year olds among Self-Reporters is over 60% which is much higher than the 47% seen in the referendum.\u00a0 There is no question that the widening gap between Self Reporters and Modellers is due to younger voters (especially women)\u00a0apparently becoming more enthusiastic about voting<\/a> and with their pro-Labour bias it is no surprise that self-reporters have seen a rapidly narrowing CON-LAB lead.\u00a0 By contrast, Modellers who place much greater weight on historical turnout see little change over the last few days.<\/p>\n
So who will be more correct on Thursday?\u00a0 I have heard a lot of talk about this being a key election for young voters “to stop their future being stolen”.\u00a0 But tweets and social media posts are far too easy to mistake for genuine enthusiasm and history is a powerful force to overcome.\u00a0 The following points make me sceptical about the supposed enthusiasm of young voters.<\/p>\n
- \n
- Nearly all pollsters have now switched to online panels.\u00a0 Only Ipsos Mori & Survation are still carrying out phone polls.\u00a0 Online panels correctly predicted a Leave vote in 2016 whereas phone polls predicted a Remain vote.\u00a0 But online panels always run the risk of recruiting techphiles and missing techphobes and the young are certainly more likely to be the former.\u00a0 The second risk is the ease of recruiting politically engaged voters who again tend to be more pro-Labour and this was ultimately blamed for the polling error of 2015 by the British Polling Council<\/a>.\u00a0 Finally, getting the referendum right doesn’t mean you will get the general election right and I have demonstrated that the demographics of the Leave vote bore almost no relation to\u00a0the\u00a0demographics\u00a0of the 2015 election<\/a>.<\/li>\n
- In 2014, Scotland recorded their highest ever turnout of 85% in their Independence referendum which was a 21% increase on the 2010 general election turnout of 64%.\u00a0 In 2015, Scottish was completely shaken up and realigned with the SNP taking 50% of the vote (up 30% on 2010) and all but wiping out Labour who had dominated Scottish politics for decades.\u00a0 It was a complete realignment of Scottish politics where again it was said that “No voters had stolen the future of the young” in the aftermath and the realignment represented an enthusiasm among Yes voters to change things.\u00a0 Does this sound familiar?\u00a0 So what happened to turnout in 2015?\u00a0 It fell from 85% to 71%, which equated to 2\/3 of the additional voters in 2014 not\u00a0bothering to vote in 2015 despite all the enthusiasm and incentive to do so since the polls were forecasting a hung parliament in 2015 giving the SNP an opportunity to play kingmaker.\u00a0 This is a real data point to take into account.<\/li>\n
- Converting young votes into seats is going to harder than Labour thinks.\u00a0 The polls are showing that Labour are closing the gap best in major cities and the South but these are the wrong places to pick these votes.\u00a0 For a start, seats with a large proportion of young voters tend to be Labour in any case.\u00a0 For example\u00a0in 2015, the Tories only had 11 of the top 67 seats where students outnumber retired people in England & Wales.\u00a0 Such seats are often university towns.\u00a0 In the South, Labour is a long way behind the Conservatives and whilst they are closing the gap, it is not yet enough to significantly hurt the Conservatives.\u00a0 If Labour want to inflict damage on the Conservatives, they need to protect their seats in the North and make gains in the Midlands and they are not doing this.<\/li>\n<\/ul>\n
Saying all that, Modellers will get it wrong if this election turns out to be a game changer.\u00a0 I have already explored the likelihood of 2017 being a realignment election <\/a>and I concluded that the answer was yes but the realignment would favour the Conservatives, such as them becoming the party of the working class.\u00a0 If something like that could happen then there is nothing to stop young voters increasing their turnout as well in which case Self Reporters will be more likely to get it right.<\/p>\n
I have decided to use the Scottish data point I referred to as a way of deciding between the two methods.\u00a0\u00a0I am taking a weighted average of the Modellers CON-LAB lead of 11.5% (2\/3 weight) and the Self-Report CON-LAB lead of 5.5% (1\/3) weight which gives an expected CON-LAB lead of 9.5%, 3% higher than the current combined average CON-LAB lead of all polls which is 6.5% (the same as 2015).\u00a0 In effect, I have decided that the Modellers are\u00a0assuming unchanged turnout of 66% in 2017\u00a0and the Self-Reports are assuming a turnout equal to the referendum of 72%.\u00a0 My weighted average implies an expected turnout of 68%.\u00a0 This estimate replicates the changes seen in Scotland where a 21% increase in turnout\u00a0from 2010\u00a0to 2014\u00a0was followed by a 14% fall in turnout in 2015 i.e. 2015 turnout was 2\/3 of 2014 plus 1\/3 of 2010.<\/p>\n
In doing this and arriving at a CON-LAB lead estimate 3% higher than the polls, I have effectively assumed that the poll average will be in error by 3%.\u00a0 This is very close to the long run 2.6% underestimate in the CON-LAB lead I identified from analysing polling errors from 1945 to 2015<\/a>.\u00a0 The nature of the error though is different this time.\u00a0 In 2015, all pollsters got it wrong but in 2017 I am saying some will get it right.\u00a0 Of course there is nothing to stop there being additional polling error on both sides of the turnout debate on top of what I have been describing here.<\/p>\n
Step 3 –\u00a0Decide if you can use Uniform National Swing (UNS) to predict seats.<\/strong><\/span><\/h3>\n
Once you have decided on your turnout model, this will give you your projected CON-LAB lead.\u00a0 Suppose we assume that Self Reporters are right and the CON-LAB lead will be 5.5% in Great Britain in 2017.\u00a0 This would be 1% lower than the CON-LAB lead of 6.5% in 2015.\u00a0 How many seats would this cost the Conservatives?<\/p>\n
Uniform National Swing (UNS) is a method that assumes that if the CON-LAB changes by 1% at a national level, on average the CON-LAB lead in every seat will also change by 1%.\u00a0 So any seat with a Conservative majority of less than 1% will be lost in such a scenario.\u00a0 How many seats are there?\u00a0 The answer is 6 listed below.<\/p>\n
- \n
- Croydon Central (London)<\/li>\n
- Derby North (East Midlands)<\/li>\n
- Gower (Wales)<\/li>\n
- Vale of Clwyd (Wales)<\/li>\n
- Bury North (North West)<\/li>\n
- Morley & Outwood (Yorkshire), Ed Balls former seat.<\/li>\n<\/ul>\n
You will notice only one of these seats is in the South, Croydon Central.\u00a0 I stated earlier that Labour is doing better in major cities and the South than in the Midlands and North and I based this on chart R1 of my opinion poll tracker<\/a>.\u00a0 This chart is based on the latest polls (both Self Reporters and Modellers) and predicts a CON-LAB lead nationally of 6.5%, exactly the same as 2015.<\/p>\n
<\/p>\nIn the Midlands, North & Wales, far from closing the gap on the Conservatives, Labour are losing ground.\u00a0 Yes they are gaining votes in these areas but the Conservatives are gaining even more with the result that either the CON-LAB lead is getting larger (Midlands)\u00a0or the LAB-CON lead is getting smaller (North & Wales).\u00a0\u00a0 In London and the South,\u00a0Labour are making larger gains\u00a0than the Conservatives\u00a0and are\u00a0narrowing the gap by 5% or so.\u00a0\u00a0But the Conservatives have very few seats in the South with such majorities and the list below is all that\u00a0Labour would\u00a0gain in London and the South based on the\u00a0changes shown in R1.<\/p>\n
- \n
- Croydon Central (London)<\/li>\n
- Brighton Kemptown (South East)<\/li>\n
- Southampton Itchen (South East)<\/li>\n
- Thurrock (East)<\/li>\n
- Bedford (East)<\/li>\n
- Plymouth Moor View (South West)<\/li>\n
- Plymouth Sutton & Devonport (South West)<\/li>\n<\/ul>\n
At the same time,\u00a0Labour would fail to take the other 5 seats I listed before in the North, Wales & Midlands and instead\u00a0the Conservatives would make the following 7 gains based on chart R1 which would cancel out these 7 losses.<\/p>\n
- \n
- NE Derbyshire (East Midlands)<\/li>\n
- Halifax (Yorkshire)<\/li>\n
- Dewsbury (Yorskshire)<\/li>\n
- Chester (North West)<\/li>\n
- Wirral West (North West)<\/li>\n
- Barrow & Furness (North West)<\/li>\n
- Lancaster & Fleetwood (North West)<\/li>\n<\/ul>\n
Then there is Scotland.\u00a0 Chart R1 shows a dramatic change around with the Nationalists down nearly 10% and the Conservatives up 15% and in second place.\u00a0 They are well set to win 5 to 10 seats and my forecast\u00a0was 8.<\/p>\n
So to summarise.\u00a0 Uniform National Swing is not a valid model as shown by the changes in chart R1.\u00a0 More than that, R1 predicts at a national level that the CON-LAB lead will be unchanged but the regional redistribution of votes means that the Conservatives will make a net gain of 8 seats.\u00a0 So an unchanged CON-LAB lead increases the number of seats for the Conservatives which raises the question, what does the CON-LAB lead need to be for them to lose seats and their majority?\u00a0 The answer is to abandon Uniform National Swing and to use a non-Uniform Regional Swing model instead.<\/p>\n
Step 4 – Take into account the variation in the Leave vote around the country<\/strong><\/span><\/h3>\n
If you have been following my General Election forec<\/a>asts, you should be familiar with my nURS model which is one of two models I now use to make my 2017 predictions<\/a>.\u00a0 Non-Uniform Regional Swing starts by working out the votes in each seat based on the changes shown in chart R1 and then adjusting the Conservative vote based on the extent to which the seat was above or below the regional average for their Leave vote share in 2016.\u00a0 Above average Leave areas see higher Conservative votes, below average Leave areas see lower Conservative votes.<\/p>\n
If you are familiar with the referendum results of 2016, you may have already spotted this pattern in chart R1.\u00a0 In London (which voted Remain) and the South (which narrowly voted Leave), Labour is closing the CON-LAB gap.\u00a0 Elsewhere in England & Wales where the Leave vote was strong, the Conservatives are either extending their lead over Labour or closing the gap on Labour.\u00a0 Scotland has to be ignored here as the political debate is influenced by the Unionist\/Natioanlist divide in addition to Brexit.<\/p>\n
This pattern is shown better in the scatter plot.\u00a0 Along the horizontal axis, I have plotted each region’s Leave vote share as a differential from the nat
ional average of 52%.\u00a0 So London which voted 40% Leave has a differential of -12% and the South East where just under 52% voted Leave has a differential of effectively zero.\u00a0 On the vertical axis, I have plotted the expected change in the CON-LAB lead in each region from 2015 to 2017 based on the latest polls in chart R1.\u00a0 Fitting the blue solid line\u00a0gives the equation of this fit in the blue label.<\/p>\nThis is a not a very good statistical fit but it is still informative.\u00a0 The blue label says that there is a CON-LAB\u00a0lead to Leave vote ELASTICITY of +0.4 i.e. for every 1% increase in the Leave vote, the CON-LAB lead increase by 0.4%.\u00a0 However, London is quite an outlier in England and would called a “high leverage” point in statistical terms, i.e. the parameters of the model as shown by the blue label are highly sensitive to any errors in the London estimate.\u00a0 I have in fact realised that in the past, my regional crossbreak analysis had a bias that overstated the CON-LAB lead in London which I have now corrected but I may still be getting it wrong.<\/p>\n
If I exclude London and recalculate the fit for regions in England & Wales outside of London, the elasticity increases to +0.62 and the fit is shown by the dashed green line.\u00a0 Again this fit is not great but bear in mind that the CON-LAB leads for all regions are simply estimates based on the polls and thus subject to error.\u00a0 However, +0.62 provides independent c
onfirmation in my mind of the mathematical basis of my nURS model as shown in the next scatter plot.\u00a0 That model uses a CON to Leave vote elasticity of +0.7 which is close enough to +0.62 to decide that my elasticity is basically on the right lines.\u00a0 The second scatter plot is based on the 5 sub regions of Wales (represented by red diamonds)\u00a0from 3 Welsh Barometer polls<\/a>\u00a0plus constituency level polls in 5 strong Remain seats (Brighton Pavilion, Bath<\/a>, Edinburgh South<\/a>, Battersea and Kensington<\/a>) which are represented by\u00a0blue and white diamonds.<\/p>\nHaving two independent analyses ending up with\u00a0similar results gives me confidence that I have a way to measure the non-uniformality of the CON-LAB lead in each seat based on the Leave vote.\u00a0 If a seat’s Leave vote\u00a0is higher than 52%, then\u00a0for every additional\u00a010pts in the Leave vote, the CON-LAB lead will\u00a0be 7pts higher\u00a0than the CON-LAB lead\u00a0shown by the polls in\u00a0chart R1.\u00a0 Conversely if a seat’s\u00a0Remain vote is lower than 48%, then for every additional 10pts\u00a0in the Remain vote, the CON-LAB lead will be 7pts lower than the\u00a0lead shown in the polls by chart R1.\u00a0 I can now use my nURS model to answer the question of at what level will the Conservatives lose their majority?<\/p>\n
Step 5 – Identify the CON-LAB lead threshold for a working majority.<\/strong><\/span><\/h3>\n
Today, the Conservatives hold 330 seats out of 650 seats which works out as a majority of 10 seats.\u00a0 At first sight, it would seem that if they lost 5 seats and ended up on 325 seats, they would lose their majority but this is not correct.\u00a0 For a start, the Speaker is elected as an independent even though he was formerly a member of the Conservative party and is not counted in the 330 seats.\u00a0 In addition, the speaker does not have a vote so if the Conservatives ended up with 325 seats, they would have a working majority of 1 seat.<\/p>\n
In fact the working majority threshold is\u00a0323 seats due to the fact that the 4 Sinn Fein MPs do not take their seats in the House of Commons <\/a>and as such do not vote.\u00a0 Out of 650 MPs, only 645 actually vote which is why the working majority threshold is 323 seats.\u00a0 This means the Conservatives need to lose 8 seats to lose their
working majority.\u00a0 I showed in step 3 that the Conservatives can expect to gain seats even if the national CON-LAB lead remains unchanged at 6.5% due to the way the votes are being redistributed unevenly by region.\u00a0 I will now use my nURS model described in step 4 to generate an election forecast for a variety of CON-LAB leads shown in the blue and green labels in table P0.<\/p>\nThe first two CON-LAB leads represent the 2 groups of pollsters, Self Reporters (5.4%) and Modellers (11.5%).\u00a0 Even if the Self-Reporters were correct, the Conservatives would gain 11 seats using nURS which would mostly come from Scotland.\u00a0 However I am sure Theresa May would be very unhappy to have only increased her working majority by 22 seats and that she is really hoping that the Modellers are right where the Tories\u00a0gain 52 seats and a 119 seat working majority.<\/p>\n
The 6.6% group represents the average of all polls today and equates to an unchanged CON-LAB lead from 2015.\u00a0 Unlike what I said in step 3 where I showed under uniform regional swing in this scenario, the Conservatives would make a net gain of 8 seats, under non-Uniform Regional Swing, they would gain a further 10 seats.\u00a0 This is the impact of Brexit becoming the main factor of the election.\u00a0 Leave seats outnumber Remain seats by 8 to 5 and this increases the Conservatives gains.<\/p>\n
To eliminate the Tories working majority, Labour has to get the CON-LAB lead down to 3.5% which is 3% lower than 2015.\u00a0 This is 4th line in the chart I showed at the beginning of the post (repeated below)\u00a0and appears as a solid brown line.<\/p>\n
<\/p>\nThe 5th and final forecast in table P0 is for my assumed CON-LAB lead based on 2:1 weighted average of the Modellers and Self-Reporters as described in step 2.\u00a0 So my official nURS forecast is\u00a0for a working majority of 89 seats.\u00a0 Bear in mind that my official election forecast is\u00a0the average of my nURS forecast and my Brexit Realignment model <\/a>(EU16R)\u00a0and in the past, EU16R has tended to give higher majorities than nURS so it is quite likely that I will still be predicting a 100+ seat majority when I publish my final forecast on Tuesday.<\/p>\n
Table P0 shows you how the number of Conservative seats is related to the CON-LAB lead and the resulting elasticity is 7.2 seats per % point.\u00a0 So if you see a poll tomorrow saying that Conservatives have an 8.5% lead over Labour, you can start with 322 seats (the threshold for a working majority)\u00a0and a CON-LAB lead of\u00a03.5%, subtract that from 8.5% to get 5pts and multiply that by 7.2 to get an additional 36 seats.\u00a0 This means the Conservatives can be expected to have 322+36=358 seats in this instance.<\/p>\n
- Nearly all pollsters have now switched to online panels.\u00a0 Only Ipsos Mori & Survation are still carrying out phone polls.\u00a0 Online panels correctly predicted a Leave vote in 2016 whereas phone polls predicted a Remain vote.\u00a0 But online panels always run the risk of recruiting techphiles and missing techphobes and the young are certainly more likely to be the former.\u00a0 The second risk is the ease of recruiting politically engaged voters who again tend to be more pro-Labour and this was ultimately blamed for the polling error of 2015 by the British Polling Council<\/a>.\u00a0 Finally, getting the referendum right doesn’t mean you will get the general election right and I have demonstrated that the demographics of the Leave vote bore almost no relation to\u00a0the\u00a0demographics\u00a0of the 2015 election<\/a>.<\/li>\n