A POLLING expert has spelled out an important caveat to a shock poll which showed Scottish Labour overtaking the SNP on the Holyrood regional list.

It comes after a survey from Redfield & Wilton Strategies, published on Wednesday evening, showed Labour had narrowed the gap with the SNP significantly in Westminster and Holyrood constituency voting intentions.

Humza Yousaf’s party polled at 35% and 36% respectively on constituency votes for both the London and Edinburgh parliaments, putting them narrowly ahead of Anas Sarwar’s Labour, who polled at 32% for both.

However, for the Scottish parliament regional list vote, Labour (on 27%) was shown to be slightly ahead of their SNP rivals (on 25%).

READ MORE: Shock poll shows Labour overtaking SNP on Holyrood regional list vote

But pollster Mark McGeoghegan told The National that a quirk in the question used by Redfield & Wilton Strategies was likely to be overinflating the Labour list vote.

The firm posed the question: “If there were to be a Scottish Parliament election tomorrow, which party would you vote for in your second (regional list) vote?”

McGeoghegan said: "In the past few Scottish Parliament elections, pollsters that characterise the regional list vote as a 'second vote' have tended to find a lower SNP list vote than there actually is on the day.

“In 2021, pollsters using 'second vote' wording underestimated the SNP list vote by an average of 5.3 percentage points, compared to an average error of just 1.4 points among pollsters not using 'second vote' wording.

“Given that, we should avoid over-relying on polls using 'second vote' wording. In a tight election, a five-point difference could significantly change the outcome.

“That said, even correcting for any 'second vote' effect, Redfield & Wilton would still have found Labour and the SNP neck-and-neck."

Marco Biagi, a former Scottish government minister who now serves as an SNP councillor in Edinburgh, also raised questions around the “second vote” terminology.

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He said: “The list vote has a long history of being commonly referred to as the ‘second’ vote, with all that implies about it being a voter’s second choice or second preference.

“The 2007 Holyrood election ballot paper fiasco [which saw several vote counts suspended and more than 140,000 ballot papers rejected] occurred in part because the Labour government of the day wanted to get rid of this ‘second’ vote issue by putting both votes on one paper, with the list vote first.

"Research after the 2003 ‘rainbow’ parliament election had found that around half the public thought the list vote was a second preference vote.”

The National:

Biagi (above) said that some of the “biggest polling misses have been in the list vote”, going on: “In 2021, there was a natural experiment where one regular pollster, Opinium, avoided using the word ‘second’ in their question. It showed list vote shares for the SNP that were consistently about 2-3 points higher than the others – and their final pre-election poll was the most accurate.

“Parties that are generally popular second choices with voters tend to do better when presented with this wording. The Greens, for example, are often the second choice of SNP and Labour voters.

“Ask any long-standing Green activist though and they’ll tell you stories of their disappointment come election day when, yet again, heady predictions of ten or more Green MSPs from the polls haven’t materialised when the actual votes were done and counted.”

Redfield & Wilton Strategies has been approached for comment.