Twelve days before Brazil's presidential run-off, set for 25 October, two polling institutes published surveys on Tuesday that both put Flávio Bolsonaro (PL) ahead of President Luiz Inácio Lula da Silva (PT) — but by distances that look nothing alike. In the BTG/Nexus poll, the gap among valid votes is 4 percentage points. In the Gerp poll, it is 10.
The two surveys interviewed voters on overlapping days and report the same margin of error, 2 percentage points either way.
What each poll found
BTG/Nexus — among valid votes, Flávio Bolsonaro has 52% and Lula 48%. Counting all responses, it is 48% to 45%, with 5% choosing a blank, spoiled or neither-of-them answer and 2% saying they did not know. In the spontaneous question, put without reading out the names, Flávio has 46% and Lula 44%.
Gerp — among valid votes, Flávio has 55% and Lula 45%. The spontaneous question shows a wider gap: 53% for Flávio and 40% for Lula, with 7% who did not know and 3% naming someone else.
Rejection and the government's rating
The two institutes point the same way on the questions that are not about vote intention, even where the numbers differ.
On rejection — the share who say they would "under no circumstances" vote for each candidate — BTG/Nexus records 51% for Lula and 47% for Flávio; Gerp has 53% for Lula and 42% for Flávio.
On the Lula government's performance, BTG/Nexus finds 50% disapproval against 45% approval. Gerp finds 49% disapproval and 45% approval. Asked to rate the government by category, BTG/Nexus respondents gave it 38% "terrible" and 15% "excellent".
How each was conducted
The BTG/Nexus survey interviewed 2,002 voters between 10 and 12 October, with a margin of error of 2 percentage points and a 95% confidence level. It is registered with the Tribunal Superior Eleitoral (Superior Electoral Court) under number BR-07997/2026, was commissioned by the bank BTG Pactual and cost R$164,888.89. The institute's previous wave was in the field between 25 and 27 September, with 2,000 respondents.
Gerp interviewed 2,400 voters on 8, 9 and 12 October, with a margin of error of 2 percentage points and a stated confidence level of 95.55%. Its registration number at the Tribunal Superior Eleitoral is BR-07877/2026, and the institute says it paid the survey's R$10,000 cost out of its own funds.
Differences in sample size, fieldwork period and who paid help explain why two portraits of the same electorate, released on the same day, do not match. It is also worth remembering that the 2-point margin applies to each percentage on its own: the distance between two candidates swings more than that figure suggests at first glance.
With information from Poder360 and Gazeta do Povo, and from the poll registrations at the Tribunal Superior Eleitoral (BR-07997/2026 and BR-07877/2026).
