Election eve: seven polls show Flávio narrowly ahead of Lula in a statistical tie

Brazil's leading pollsters released their final surveys on Saturday (Oct. 24), ahead of the presidential runoff on Sunday (Oct. 25). In every survey, Flávio Bolsonaro (PL) is narrowly ahead of Lula (PT), but by margins within or at the edge of the margin of error, which amounts to a statistical tie. In the first round, Flávio won 47.03% of valid votes and Lula 45.16%.

What the numbers show

Datafolha, commissioned by Folha de S.Paulo and TV Globo, put Flávio at 51% and Lula at 49% of valid votes. Among all respondents, the score was 48% to 47%. In Thursday's (Oct. 22) round, the two were tied at 50% of valid votes. The pollster also measured rejection: 46% say they would never vote for Lula, and 45% reject Flávio. In the previous survey, those figures were reversed.

Quaest, commissioned by Globo, also found 51% to 49% of valid votes and 46% to 45% overall. Both candidates gained 1 point from the previous round, while blank, null and undecided responses declined.

AtlasIntel put Flávio at 50.8% and Lula at 49.2%, with a 1-point margin of error. In the round released on Oct. 19, the score was 51.1% to 48.9%. The CNT/MDA poll, released in the morning, showed 50.7% to 49.3% of valid votes and 46.3% to 45.0% overall. Nexus, commissioned by BTG Pactual, found 50.5% to 49.5%.

Palver released only overall figures: Flávio at 50% and Lula at 49%, compared with 50% to 48% in its Oct. 21 round. Gerp showed the widest gap of the day, 52% to 48% of valid votes, after 53% to 47% in its previous round.

Pollster comparison (valid votes, Flávio vs. Lula)

• Datafolha: 51% vs. 49% (overall 48% vs. 47%; margin 2 pts; previous 50% vs. 50%)
• Quaest: 51% vs. 49% (overall 46% vs. 45%; margin 2 pts; previous about 50.6% vs. 49.4%, Poder360 estimate)
• AtlasIntel: 50.8% vs. 49.2% (margin 1 pt; previous 51.1% vs. 48.9%)
• CNT/MDA: 50.7% vs. 49.3% (overall 46.3% vs. 45.0%; margin 2.2 pts; previous 50.5% vs. 49.5%)
• Nexus/BTG: 50.5% vs. 49.5% (margin 2.2 pts; previous 50.3% vs. 49.7%)
• Gerp: 52% vs. 48% (margin 2 pts; previous 53% vs. 47%)
• Palver: overall only, 50% vs. 49% (margin 2.2 pts; previous 50% vs. 48%)

What a statistical tie means

Every sample-based poll has a margin of error. With a 2-point margin, a candidate polling at 51% could in practice be anywhere between 49% and 53%. When the two candidates' ranges overlap, it is not possible to say statistically who is ahead. That applies to every poll released today; in Gerp's case, the 4-point gap sits exactly at the edge of the margin. Polls capture the moment they were taken and are not forecasts of the result.

What to watch on Sunday

Polls are open from 8 a.m. to 5 p.m. Brasília time nationwide. The Superior Electoral Court (TSE) begins releasing results at 5 p.m. on resultados.tse.jus.br and in the Resultados app as ballots are counted. Turnout and the candidates' regional performance are expected to be the key things to watch during the night.