Election polling company Ipsos B&A has blamed a decline in turnout and an unwillingness of older voters to take part in interviews for errors in its general election exit poll.
The Ipsos/B&A poll conducted for The Irish Times, RTÉ, TG4 and Trinity College Dublin – published as voting stations closed at 10pm on Friday – put Sinn Féin on 21.1 per cent, Fine Gael 21 per cent, and Fianna Fáil 19.5 per cent, with a 1.4 percentage point margin of error.
However, the actual results show the poll was out by as much as 2.4 points, with Sinn Féin on 19 per cent and Fine Gael on 21 per cent, but Fianna Fáil on 21.9 per cent.
Ipsos B&A president Damian Loscher said there was “no simple answer” as to why this election’s exit poll was not “more predictive”.
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However, he said the slightly lower turnout in 2024, compared with 2020, may have been a factor.
“How this change manifested itself across rural and urban stations will need to be examined for any potential impact on party share predictions,” he said.
He also cited refusal rates to engage in interviews with pollsters, with indications that refusals were “heavily biased” towards older voters.
“We know older voters favour Fianna Fáil, so a higher rate of refusals among older voters would have depressed their predicted vote share,” he said.
“The collection of accurate age data for those who refuse to take part for use in data weighting is likely to be incorporated into future models, especially as anecdotally the levels of refusals in exit polls are on the increase.”
The time of voting may also have been a factor, Mr Loscher said.
“Time of day matters because the party preferences of late evening voters are very different from, say, midmorning voters. For a party like Sinn Féin, the evening vote, when more young people come out, is vital,” he said.
However, he conceded it was unusual for the accuracy of predictions for two parties to be outside the margin of error.
“One party share prediction outside the margin of error is not that rare, but two – both Fianna Fáil and Sinn Féin share predictions sat outside the plus or minus 1.4 percentage points range – suggest a source of deviation beyond the expected margin of error, such as turnout and high refusal rates among older voters,” he said.
“With turnout and willingness to participate in exit polls declining, enhanced accuracy will require prediction models to evolve to meet the growing unpredictability of voters.”
While there was an expectation exit polls would be the most accurate of all polls conducted before counting starts, they were “not as straightforward as they seem, or as pollsters would like”, Mr Loscher said.
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