by Marcelo Hailer
Political scientist Felipe Nunes, the director of the polling firm Quaest, has identified voter abstention as a potential surprise factor in the presidential runoff between President Luiz Inácio Lula da Silva and far-right Senator Flávio Bolsonaro, this Sunday, October 25.
His analysis came following the release of the latest Quaest poll this Saturday, October 24, which showed Flávio Bolsonaro with 51% of the valid votes, ahead of Lula with 49%. It’s a statistical tie, given the two-percentage-point margin of error.
Brazilian President Luiz Inácio Lula Da Silva waves a Brazilian flag on top of a pick-up truck during a rally in Rio de Janeiro, on October 24, 2026. (Photo by Wagner Meier/Getty Images)
According to Nunes, if abstention rates turn out to be lower than what the poll currently estimates, the landscape of the race could shift, in particular because, in his assessment, Lula is the candidate most disadvantaged by voter absence at the polls.
“However, if tomorrow’s abstention rate comes in lower than what we are projecting, we could see a surprise, because Lula is the candidate most penalized by abstention,” he stated.
Felipe Nunes highlights the stability of the vote for both Lula and Flávio
In Nunes’ view, the key variable in the final stretch is not the shifting of votes between the two candidates, but rather voter turnout this Sunday.
This is because, according to the data presented by Nunes, both Flávio Bolsonaro and Lula have achieved high levels of voter consolidation.
“The real key in this final stretch isn’t a change in votes,” he explains. “That remains consistent: Flávio has 97% of his voters locked in, and Lula has 95%.”
In his analysis, the percentages cited by the political scientist indicate that the vast majority of voters for both candidates have already firmly made up their minds. Consequently, the participation of those not yet firmly aligned with either side will have greater significance in the contest.
Independent voters could spring a surprise in the runoff.
Felipe Nunes drew particular attention to independent voters, who, according to him, account for 16% of the Brazilian electorate.
Nunes suggested that the decision by this group to head to the polls could lead to a different outcome from what current turnout estimates imply.
“Looking at this data,” he said. “What could come as a surprise tomorrow is this group of independents, 16% of the Brazilian electorate, which is a significant number of people, who might decide: ‘You know what? I’m going to participate; I won’t abstain’.”
“This could be the surprise of the election,” he said.
This assessment comes against the backdrop of a tight race. In a Quaest poll released this Saturday, October 24, Flávio Bolsonaro appeared numerically ahead of Lula, but the two-percentage-point gap fell within the margin of error.
The survey, commissioned by TV Globo and the newspaper O Globo, polled 3,702 voters between October 23 and 24, with a 95% level of confidence.
This article was originally published by Revista Forum. It was translated by Panamerican Dispatch. You can read it in its original Portuguese, here.