Nigel Marriott – Page 32

UK General Election 2017 #7 – Review of my predictions

July 9, 2017 By Nigel Marriott

Exactly one month ago, the UK woke up to the news they had elected a hung parliament for the second time in three elections. For many forecasters including myself, this came as a surprise as I had been predicting a Conservative majority of 100 seats. In the event, the largest ever polling underestimate of the Labour vote was enough to see the Conservatives lose their majority.

At the beginning of my commentary on election night itself, I defined success for my forecasts as being how close the number of Conservative seats was to my forecast of 375. I also stated that if the number of seats was in the 340s I would consider this to be a prediction error. The final outcome was 317 seats so clearly that is a major prediction error.

**Update 20th Sept 2025 – This post was originally published 9th July 2017. It remains one of my most important posts but it did contain some graphics which were unreadable in some formats and some typos so I’ve edited this post to correct these issues. I’ve also updated the text format to my current style guide and taken the opportunity to add links to subsequent posts which reinforce particular points made in this article. Any new links are pointed out**

UK Weather Tracker #5 – June 2017

July 7, 2017 By Nigel Marriott

My latest UK weather tracker shows that the meteorological summer started with a hot but stormy June.

UK General Elections #2 – How accurate are the opinion polls? – updated with GE17

July 2, 2017 By Nigel Marriott

Ahead of the 2017 general election, I predicted that the opinion polls would be wrong again and that the Conservatives lead over Labour would be underestimated by 2.6%. I based this on data provided by Mark Pack who has systematically recorded every opinion poll published since 1945. In the event, I was right that the polls would be wrong but instead of an error favouring the Conservatives, the polls recorded the largest ever underestimate of the Labour vote. As a result, election forecasters were blindsided yet again and the result was a hung parliament which few saw coming.

UK Weather Tracker #4 – May 2017

June 25, 2017 By Nigel Marriott

I apologise for the lateness of this post. The general election took up a lot of my time and energy but from now on I have no excuse not to keep this up to date.

My latest UK weather tracker shows that it was the 2nd warmest May since 1910.

UK Weather Trends #1 – Spring 2017

June 25, 2017 By Nigel Marriott

Meteorologists define spring in the UK to be the period from March to May so spring is now over and we are officially in summer. I have decided to create a series of posts which I will publish at the end of each season showing how that season compares to the weather record. The 2017 spring turned out to be the 2nd warmest on record.

UK General Election 2017 Results #1 – My Election Night Commentary

June 9, 2017 By Nigel Marriott

Friday 07:35 – I’ve just woken up to the result that we have a hung parliament which is miles away from my prediction. Clearly I need to conduct a post-mortem of my model but I did state in my first chart of this post (see bottom of post) that a hung parliament would occur if the CON-LAB lead was under 3%. Sure enough that is the outcome with the BBC currently saying the CON-LAB lead is 2.3%. What it also means that we have another epic polling error as the average of all polls in the week before the election showed a CON-LAB lead of 7.5%. Unlike 2015 when all pollsters got it, congratulations must go to Survation who called it spot on.

I am sure we will have a wave of people claiming to have predicted this error. As far as I am concerned a valid prediction is only one made in public in advance. Such a prediction would also need to explain why they expected a polling error on the scale shown in the chart.

The last time such an error occurred was 1983 and the error is on the scale of 1951! In fact the error is even more remarkable if you look at the 3 main parties.

Another polling post mortem beckons but this election will go down in history.

UK General Election 2017 #6 – Everything you need to know in one place!

June 6, 2017 By Nigel Marriott

Over the last 6 weeks I have been making many posts about what is happening and what will happen in 2017. I thought it would be helpful to have one post which brings everything together in one place.

My official 2017 election forecast summarises what I expect the results to be on June 8^th 2017. This post also includes a link to a spreadsheet containing my seat by seat forecasts which can be found at the bottom of that post. (EDIT: Weds 7th June @1030AM. If you downloaded the spreadsheet before 1030 on Weds 7th June, please visit the link and download the spreadsheet again. The link explains why)

To accompany my forecast, I have created 4 youtube video clips where I dig into the details of how I arrived at that forecast.

UK Opinion Poll Tracker #6 – 4th June 2017

June 6, 2017 By Nigel Marriott

This is my last update of the opinion before election day on June 8th. I will use my analysis of these polls to update my 2017 General Election Seat Predictions and you should read that post in conjunction with this one.

The latest situation is that the Conservatives now only hold a 7% lead over Labour which is down 2% from last week and only just above what they had in 2015. Labour’s vote share has recovered significantly to narrow the Conservatives lead and Labour are now capable under some scenarios of depriving the Conservatives of a majority. However, it has now become clear that pollsters are dividing into two groups and I have written a separate post that explores the implications of this and I strongly recommend you read that. This post reports on all posters combined rather than separate blocs.

UK General Election 2017 Forecast #4 – My Official Prediction as of 4th June 2017

June 6, 2017 By Nigel Marriott

My official prediction using my Final Election Model is that the Conservatives will make a net gain of 45 seats resulting in a working majority of 105 seats.

My forecast uses data from my latest UK Opinion Poll Tracker and it is worth reading that post in conjunction with this post. At the bottom of this post is a spreadsheet containing my prediction for each seat. I am basing all figures in this forecast on the assumption that Conservatives will have a 9.5% lead over Labour on June 8th. I arrive at that figure by taking the current CON-LAB lead of 7% in the latest polls and adding an expected 2.5% underestimate in the Conservative lead over Labour based on my analysis of historical polling errors. A knock-on effect of this assumption is that I expect turnout to be 2pts higher at 68%.

UK General Election 2017 Forecast #5 – 5 steps to making sense of the latest polls!

June 4, 2017 By Nigel Marriott

Unlike the 2015 general election when the polls were essentially static (& wrong) throughout the election, the 2017 general election has seen some of the most extraordinary volatility in the polls that I can remember. If you are a Conservative supporter, the narrowing lead over Labour must be leading to anxiety and changed underwear. If you are a Labour supporter, you are probably starting to dream “can we? will we?!” It doesn’t help that your state of mind will depend on which poll you are reading and your memories of the pollsters’ failure in 2015 so how can you make sense of what is going on. I will show you how in 5 steps and to heighten the drama, I will leave the punchline to the end!