Exit Poll 2019

[AdminSTB]

All the BBC exit polls between 1992 and 2019:

[nodealbrexiteer]

Jan 6, 2020 23:04:09 GMT AdminSTB said:

All the BBC exit polls between 1992 and 2019:

Thank you-someone else has put one on for October 1974 to 2017 I think. Pity it's pretty much impossible to do one for ITN!

[nodealbrexiteer]

Dec 16, 2019 10:09:24 GMT Robert Waller said:

I don't think the individual seat projections in the exit poll was a very good idea, as it detracts from the impression of its overall accuracy. I note that in the BBC coverage they didn't show Jeremy Vine's 'wall' much as the night went on. I know of at least one viewer who thought that colouring it in meant the seat had actually changed hands, for example Cities of London and Westminster. Sky didn't use the seat predictions, not sure about ITV.
I believe they only polled in 144 constituencies, leaving over 500 with no sample at all.
The idea is not to produce any kind of national vote share, but to look at the situation in different types of marginal contest.
A key element is that they use the same polling stations as last time and calculate changes in these.
Inevitably they will miss factors that affect individual seats.
The only real overall weakness was Scotland. As John Curtice pointed out, they had few polling stations there and were far less confident about the situation 'north of the border'.

I also thought they were slow in updating the overall projection, for example the SNP was still projected to get 52 when it was obvious that the would get fewer.

Overall, though, the methodology still worked pretty well.

Just out of interest when you worked on the ITN/Harris General Election exit polls how would you say there seat projection methodology worked please? A uniform swing projected across the relevant type of marginal seats or was the model more complex like the BBC's?

[Robert Waller]

A uniform swing projected across the relevant type of marginal seats, plus a few adjustments for individual seats that didn't fit general patterns. It worked well in 1987, but in 1992 it slightly underestimated the Conservatives, though the decision was made to say this suggested a hung parliament with C largest party.
With hindsight, I would now recommend we had just said 'C largest party' at 10 pm in 1992, and waited for some actual results to come in...

[nodealbrexiteer]

Apr 29, 2020 20:15:39 GMT Robert Waller said:

A uniform swing projected across the relevant type of marginal seats, plus a few adjustments for individual seats that didn't fit general patterns. It worked well in 1987, but in 1992 it slightly underestimated the Conservatives, though the decision was made to say this suggested a hung parliament with C largest party.
With hindsight, I would now recommend we had just said 'C largest party' at 10 pm in 1992, and waited for some actual results to come in...

Thank you! I always understood ITN used a simpler technique. I would imagine ITN did the same in October 1974,1979 and 1983? And what of the mystery ITN February 1974 forecast I mentioned in the 'Interesting electoral facts' thread(and indeed the BBC one that year)

I guess in 1987 it was a case of tweaking figures to allow for some Tory gains from Labour and the Alliance. I don't know if you should beat yourself up over 1992. The seat forecast was a little closer than the bBC with their more elaborate model and bear in mind the marginals poll like the BBC's found a bigger swing there than nationally. Though Jon Snow says at the start of the programme something like 'we had had thought of not making a seat projection as it's so close' and he did emphasise the better Labour performance in the marginals. 1997 appears to be the only election since nationwide exit polling started where one of the channels didn't broadcast it's seat projection(BBC).

Mind you when the BBC used other sources of information like the poll of polls in 1979 instead of a marginals exit poll I wondered what information they gleaned rom it to arrive at their forecast. Also in October 1974 why their official on screen forecast was not computer based and done by Professor Michael steed but the authors of the forecasting programme(Dr Clive Payne Professor Philip Brown) that Professor Graham Pyatt was using on air did their own computer forecast based on the exit poll and came closer(but this forecast was not officially aired)