YouGov - 28-29 April 2019 (NB date - posted out of sequence) - with polling on a Remain platform

London4Europe Committee Member Michael Romberg works out what the opinion poll findings for the European Elections in London mean for seats. Remember: it’s just a poll – a snapshot that comes with a significant margin of error. The margin is bigger than usual because London respondents are just a small subset of the overall sample.

Data Source:  YouGov - fieldwork 28-29 April 2019  -  213 replies in London,  tables exclude don't know/ won't say/ won't vote (24 % of London sample).

An opinion poll about a Remain Platform

This poll is interesting because it asks about a common Remain platform. The poll does not do the simple arithmetic sum that I do in table 2 below. Rather, it asks the panel of respondents how they would vote if instead of facing individual Remain candidates they faced a single Remain candidate chosen from one of the three parties.  

At the England level, the voting figures would not be that different: in the range 26-30% for a platform depending on which party fielded the candidate; as opposed to 27% for the parties standing separately.

YouGov assess the effect in London - a large constituency - as being 2-3 seats for a platform as opposed to 2 seats for parties standing separately. In smaller constituencies there would be a bigger effect on seats. 

In London, excluding don't know,  32% is the sum of the individual parties and the score depending on which party was chosen to represent the platform would be: only Change UK 34%, only Liberal Democrats 36%, only Greens 40%.

With these numbers, Tables 3-5 show that only with the 40% score would the Remain party have won enough extra votes to win one extra seat.

Please note, the sample size is too small to draw real conclusions from a single poll. It has also, to some extent, been superseded by the effects of the local government elections and other developments since its fieldwork. 

The conclusion that I draw is that the comparison I have been making in Table 2 in this series of blogs is a reasonable approximation to the effect that a single Remain platform would have had. 

It is worth reading the article on YouGov to learn more.

Seats implied by the opinion poll

TABLE 1: This table takes the opinion poll findings and turns them into seats using the D’Hondt method (read more about that here). Seats won in each round are shown in bold. Poll numbers are then adjusted for subsequent rounds of seat allocation.

Notes

Brexit = Farage’s Brexit Party

Change UK, formerly The Independent Group of MPs

LD = Liberal Democrats

CAVEATS

• It’s a poll. A snapshot in time. People’s views change. If “don’t know/ won’t say” is large, then their views could swamp small differences between parties once they decide.
• European elections normally have low turnout. Differential turnout amongst supporters of different parties could affect the result compared with a poll. Different polling companies have different methodologies for adjusting for turnout.
• The definition of “London” in the poll may not match the London constituency for the election.
• Polls come with a margin of error. On the highest level figures asking a question of the whole sample a rule of thumb is that polls come with a margin of +/- 3 percentage points (so 45% think this might be anything in the range 42%-48%). London figures are normally a small subset of the poll so the margin of error is larger. A good overall sample size for a poll is 2,000 or so.
• My calculations are on rounded numbers and that might introduce an error when results are close.

TABLE 2: this table works out a counterfactual allocation of seats if the Remain parties had joined on a single platform. The calculation assumes that the vote for the platform would be the sum of the votes for the individual parties. That would not be the case in real life – there are arguments for saying that a platform might do better or that it would do worse than the sum of the parties. 

In the case of this poll a common Remain Platform would have made no difference to the total seats won by the various parties/ platform. 

Remain = sum of poll results for Change UK, Green and Liberal Democrats

TABLE 3:  using the opinion poll data, what if only Change UK had stood? No increase in the number of Remain seats

TABLE 4: using the opinion poll data, what if only the Liberal Democrat Party had stood? No increase in the number of Remain seats

TABLE 5: using the opinion poll data, what if only the Green Party had stood? The number of Remain seats would have increased by one.