After 12 months of essentially static polls despite the news being dominated by Brexit, Labour has experienced a significant worsening of their position and the Conservatives have opened up a lead over Labour that would give them a majority in parliament. Words of caution are being uttered about the extent of the Tory lead since one pollster is notably out of step with all other pollsters.
The Conservatives have lost their lead over Labour but despite the parliamentary turmoil over Brexit in December, the polls do not show much movement in the grand scheme of things.
Here is a long overdue update of my UK opinion poll tracker and in this post, I going to take a closer look at the key trends over the last 12 months.
As I write this, a plethora of economic forecasts are making the rounds in the news in the UK. In all cases, the forecasters have failed to publish their track record and these days, I will not pay attention to what they say unless their forecasts are accompanied by a track record. But, how does one go about presenting a forecasting track record to prove that one has forecasting skill? To demonstrate, I will analyse how well opinion polls have predicted General Elections in the UK and measure their track record. I must confess I was surprised at what I found out and I would urge all opinion pollsters to take note of my results.
For my latest Opinion Poll Tracker, I will explore 4 points currently being debated by political pundits.
- Have the Conservatives taken the lead in the polls?
- How much weight should we give to Survation polls who were the most accurate in 2017 and are the outlier poll today?
- Was there a “Youthquake” in the 2017 general election?
- What would the effect be of allowing 16 & 17 year olds to vote in general elections?
The last 3 general elections have seen some significant polling errors. In 2010, the Lib Dems were significantly overestimated, in 2015 the Conservatives were underestimated and last year saw the largest ever underestimate in the Labour vote. Whilst these errors suggest that the polling industry is struggling with general elections these days, a natural question to ask is “are all pollsters equally bad or are some better than others?”
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.
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.
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!
As I have explained, I track the regional breakdowns to produce this chart. Every now and again, a full on poll takes place to explore a region in more detail and this allows me to check how good chart R1 is.