Two Brazil Runoff Polls Put Different Men in Front. The Difference Is a Telephone.
BRAZIL · ELECTION
Key Facts
- —The election Brazil votes for a president in early October, and few expect it to end in one round.
- —The contenders President Lula, now 80, against Flávio Bolsonaro, senator and son of the previous president.
- —Poll one Quaest sent interviewers to people’s homes. It found Flávio Bolsonaro ahead, 42 to 40.
- —Poll two Nexus telephoned a similar sample on overlapping days. It found Lula ahead, 47 to 46.
- —The agreement Both give Lula the same five-point lead in the first round. That margin is identical.
- —The catch Neither lead clears the margin of error. Both races are ties dressed up as results.
Both polls were in the field on the same days, testing the same names. Then they published headlines that contradicted each other.
On Monday Brazil woke to two Brazil runoff polls that appeared to describe different countries. One had the challenger winning, the other had the president holding on.
Both were taken in the same week, testing the same six candidates. The explanation is not politics but the way the questions were asked.
The Election Everyone Is Measuring
Brazilians vote for a president on the first Sunday of October. If nobody clears half the vote, the top two meet again three weeks later.
Nobody expects anyone to clear half. So the polls that matter are the ones testing that second round.
On one side is Luiz Inácio Lula da Silva, 80 years old and in his third term. He has been the dominant figure in Brazilian politics for a quarter of a century.
On the other is Flávio Bolsonaro, a senator and the eldest son of Jair Bolsonaro, the president Lula replaced. He carries his father’s movement and his father’s legal problems.
What the Two Brazil Runoff Polls Found
Quaest, published for the Globo media group, put Flávio Bolsonaro ahead by 42% to 40%. Its interviewers went to people’s homes with tablets.
Nexus, published for the investment bank BTG Pactual, put Lula ahead by 47% to 46%. Its interviewers used the telephone.
Quaest was in the field from 10 to 13 September, Nexus from 11 to 13. Three of the four days overlap.
Both tested the same six names. Both surveyed just over two thousand people.
Neither result is outside the margin of error, which both put at two points. In the language of polling these are two ties.
The Number Nobody Led With
Turn to the first round and the two surveys stop disagreeing entirely. Quaest has Lula on 36% and Flávio Bolsonaro on 31%.
Nexus has them on 42% and 37%. The levels differ by six points in both cases.
The gap between the two men is five points in each poll. Two firms, two methods, one answer.
The other candidates line up as neatly. Cury takes 7% and 6%, Caiado 4% and 5%, Zema 1% in both.
Why the Telephone Changes the Answer
A person on the telephone is talking to a stranger and wants the call to end. Asked to choose between two names, most choose one.
A person on their own doorstep has time to say they have not decided. The interviewer waits, and the answer stays open.
The arithmetic shows it plainly. In the Quaest second round, 42 plus 40 leaves 18% of voters unassigned.
In the Nexus second round, 47 plus 46 leaves 7%. That eleven-point gap is the entire disagreement.
The same pattern appears in the first round, where Quaest records 10% undecided against Nexus on 2%. Neither firm is wrong.
They are measuring the same electorate through different instruments. Instruments have personalities.
The Trend That Is Real
Comparing two firms tells you about polling. Comparing one firm with itself tells you about voters.
Quaest has now run the same question three times in a fortnight, the same way each time. On 2 September Lula led by one point.
On 7 September it was level at 41 each. On 14 September Flávio Bolsonaro led by two.
That is a drift of three points towards the challenger in twelve days. It is small, and unlike the headline contradiction it is genuine.
Other Brazil runoff polls bracket it. Datafolha had Lula ahead by two on 11 September, while AtlasIntel, polling online, had Flávio Bolsonaro nominally ahead.
One Number to Read Carefully
Both polls asked about the government twice, in ways that are not interchangeable. Quaest found 43% approving and 50% disapproving.
Asked instead to rate the government, 38% of the same sample called it bad or terrible. That is twelve points below the disapproval figure.
Nexus shows the same effect more gently, with 49% disapproving and 44% rating it badly. Approval and rating are different questions about the same president.
In the weeks ahead both numbers will be quoted as though they were one. They are not, and the gap between them is wide enough to win an argument with.
More: Brazil news in English, every day from The Rio Times.
Frequently Asked Questions
Which of the two Brazil runoff polls is right?
Both, within their own margins. Each shows a statistical tie, and each gives Lula the same five-point first-round lead over Flávio Bolsonaro.
Why do the headline numbers differ?
Quaest interviews people at home and leaves 18% of second-round voters unassigned. Nexus telephones and leaves 7%. A telephone call pushes undecided voters into naming someone.
Who are the candidates?
President Luiz Inácio Lula da Silva, 80, seeking a fourth term, and Senator Flávio Bolsonaro, eldest son of former president Jair Bolsonaro. Four other names are polling in single figures.
When does Brazil vote?
The first round falls on the first Sunday of October, with a runoff three weeks later if nobody wins more than half the vote. No candidate is close to that.
Has Flávio Bolsonaro taken the lead?
Not in any meaningful sense. His two-point margin sits inside a two-point margin of error, and a poll published the same day has Lula ahead.
Sources: Nexus Pesquisa e Inteligência release of 14 September, Poder360, Gazeta do Povo, Brasil de Fato, CartaCapital, Metrópoles and Correio Braziliense.
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