(This Oct. 3 story has been refiled to fix spelling of name in paragraph 5 to Andrei Roman)
BRASILIA (Reuters) - The first round of Brazil's presidential election has come and gone with no final victor, but some big losers have emerged: opinion pollsters.
Surveys in Brazil had leftist challenger Luiz Inacio Lula da Silva up anywhere from 7 to 17 percentage points over right-wing President Jair Bolsonaro in the weeks leading up to the election, with some suggesting he could reach the 50% threshold in Sunday's vote needed to avoid a runoff on Oct. 30.
When Brazilians cast their ballots, however, Lula's lead over Bolsonaro was just over 5 percentage points, setting the two up for an unexpectedly competitive runoff. In some Senate and gubernatorial races, Bolsonaro allies outperformed opinion polls by more than 20 points.
Coming after major misses in U.S. elections and the 2016 Brexit referendum, where surveys failed to detect the depth of conservative sentiment, Sunday's result in Brazil has public opinion firms scratching their heads once again.
Andrei Roman, chief executive of pollster AtlasIntel, said a mea culpa was in order.
"The 9-point different predicted by Atlas turned out to be only 5 points in the results," he wrote on Twitter on Monday. "We have to confront this disconnect with honesty."
Pollster IPEC, which had projected the widest margin, said that its numbers showed Lula would finish ahead but a runoff was far from guaranteed. In a statement, the firm attributed the outperformance of Bolsonaro to last-minute switches from the supporters of less popular candidates. IPEC added that it was analyzing its methodology with respect to state-level races.
Political analysts said the polling flub was likely the result of several factors, some unique to Brazil but others reflecting global trends.
A right-wing populist often criticized for comments about women and minorities, Bolsonaro has plenty of silent supporters who are reluctant to tell pollsters they support such a controversial firebrand, said Creomar de Souza, chief executive of Dharma Political Risk.
The same phenomenon appears to have helped former U.S. President Donald Trump outperform most polls in the 2016 and 2020 elections.
DELAYED CENSUS
But Brazilian pollsters are also feeling their way in the dark. There has been no national census since 2010 because of the COVID-19 pandemic, making it difficult for firms to calibrate a representative sample of respondents, de Souza said.
Brazilian society is changing fast, with the right-leaning evangelical Christian vote, for instance, rapidly expanding.
Another factor: former president Lula may have been a victim of his success. Some surveys in the final weeks showed him expanding his lead enough to win outright in the first round, which may have spooked conservative voters into abandoning more centrist candidates to shore up Bolsonaro.
Lula had largely declined to comment on those polls in an apparent attempt to keep his base mobilized - and to avoid mobilizing conservatives - but it was to little avail.
"It seems that the tactical votes went to Bolsonaro," said sociologist and political scientist Antonio Lavareda.
Finally, analysts said, conservatives in Brazil - as elsewhere - appear simply to distrust pollsters.
That may be feeding a vicious cycle in which conservatives decline to respond, leading the polls to underestimate their favored candidates, which only reinforces their distrust.
Bolsonaro has spent much of his four-year term bashing major polling firms and his allies are banging that drum again with vigor. His chief of staff, Ciro Nogueira, called on supporters to ignore the pollsters for the rest of the election.
"After the scandal that they committed, all Bolsonaro supporters have only one response to the polling companies: Don't respond to any of them until the end of the election!!" Nogueira wrote late Sunday on Twitter.
"They were absurdly wrong, criminally, no? Only an extensive investigation can reveal what happened."
(Reporting by Maria Carolina Marcello in Brasilia and Gram Slattery in Rio de Janeiro; Writing by Gram Slattery; Editing by Brad Haynes, Grant McCool and Richard Pullin)
