Candidates for the Senate of MT — Photo: Reproduction
Quaest research released this Saturday (3), the eve of the 1st round, shows how the dispute for the Senate is going in Mato Grosso. This Sunday (4), each voter will have to vote for two candidates. Mauro Mendes appears in the lead in the polls. Janaína Riva comes in second place followed by Zé Medeiros, in third place. Fávaro and Pedro Taques appear technically tied.
Spontaneous search
First, Quaest asked voters who they would vote for, without showing the list of candidates. This is a spontaneous survey, and 58% of respondents did not mention a name in their response. Therefore, they are considered undecided (at the end of the report, see data from the spontaneous survey).
The results of the spontaneous survey help to measure the degree of vote consolidation. The greater the number of undecided voters the day before, the less consolidated the vote is and the greater the possibility of changes in relation to Sunday's result.
Stimulated search - valid votes
In the stimulated survey, the names and parties of the candidates are presented to the interviewees. Each voter chooses a name for the first vacancy in the Senate and another for the second.
The data below considers the votes valid. This calculation excludes blank and invalid votes and also undecided voters.
Mauro Mendes (UNIÃO): 37%
Janaína Riva (MDB): 23%
Zé Medeiros (PL): 17%
Fávaro (PSD): 9%
Pedro Taques (PSB): 9%
Galvan (FORWARD): 2%
Margareth Buzetti (PP): 2%
Colonel Darwin (DEMOCRAT): 1%
Beny Godoy (ACT): 0%
Professor Nelson Ferreira (AGIR): 0%
What are valid votes?
This is the way in which the TSE publishes the official results of the elections. These are the votes cast for candidates. This calculation leaves out blank and invalid votes and abstentions. To win in the 1st round, a candidate needs 50% of the valid votes plus one vote.
How does Quaest calculate valid votes?
Quaest takes into account voting intentions from the survey and the turnout profile to estimate valid votes. It is the likely voter model, which considers voters with a greater propensity to vote.
Stimulated Search - Total Votes
See now the numbers of total votes, including blank and invalid votes and undecided votes.
Aggregate result (1st and 2nd wave)
Mauro Mendes (UNIÃO): 26% (it was 27% on September 25)
Janaína Riva (MDB): 16% (was 19%)
Zé Medeiros (PL): 11% (was 9%)
Pedro Taques (PSB): 6% (was 9%)
Fávaro (PSD): 5% (was 8%)
Colonel Darwin (DEMOCRAT): 2% (was 2%)
Galvan (FORWARD): 2% (continues 2%)
Margareth Buzetti (PP): 2% (was 1%)
Professor Nelson Ferreira (AGIR): 0% (was 1%)
Beny Godoy (ACT): 0% (was 0%)
Blank/null/will not vote: 7% (was 5%)
Undecided: 23% (was 18%)
Vote for 1st place
Mauro Mendes (UNIÃO): 39%
Janaína Riva (MDB): 17%
Zé Medeiros (PL): 11%
Fávaro (PSD): 5%
Pedro Taques (PSB): 4%
Colonel Darwin (DEMOCRAT): 2%
Galvan (FORWARD): 1%
Margareth Buzetti (PP): 1%
Professor Nelson Ferreira (AGIR): 0%
Beny Godoy (ACT): 0%
Blank/null/will not vote: 6%
Undecided: 14%
Vote for 2nd place
Janaína Riva (MDB): 16%
Mauro Mendes (UNIÃO): 12%
Zé Medeiros (PL): 10%
Pedro Taques (PSB): 8%
Fávaro (PSD): 6%
Galvan (FORWARD): 3%
Colonel Darwin (DEMOCRAT): 2%
Margareth Buzetti (PP): 2%
Professor Nelson Ferreira (AGIR): 1%
Beny Godoy (ACT): 0%
Blank/null/will not vote: 9%
Undecided: 31%
Vote decision
For 20%, the vote choice for the Senate could still change. Another 80% say the decision is final.
Choice is final: 80% (it was 63% on September 25)
May change: 20% (was 37%)
Don't know/didn't answer: 0% (was 0%)
Spontaneous search
Mauro Mendes (UNIÃO): 13% (it was 9% on September 25)
Janaína Riva (MDB): 9% (was 6%)
Zé Medeiros (PL): 7% (was 4%)
Fávaro (PSD): 3% (was 4%)
Pedro Taques (PSB): 2% (continues 2%)
Galvan (FORWARD): 1% (continues 1%)
Margareth Buzetti (PP): 1% (was 0%)
Colonel Darwin (DEMOCRAT): 0% (was 0%)
Beny Godoy (ACT): 0% (was 0%)
Professor Nelson Ferreira (AGIR): 0% (was 0%)
Blank/null/will not vote: 6% (was 5%)
Undecided: 58% (was 69%)
The survey was commissioned by Rede Matogrossense de Comunicação (RMC) and interviewed 1,800 voters aged 16 or over, between the 2nd and 3rd of October. The margin of error is 2 percentage points, plus or minus. The confidence level is 95%. The survey was registered with the Electoral Court under number TSE: MT-02649/2026.
