André Ventura has 75% chance of reaching the second round
Based on the latest polls, there is a >99% probability of a second round being needed.
Runoff probabilities
André Ventura
Gouveia e Melo
Marques Mendes
António José Seguro
Cotrim Figueiredo
ℹ️ New metric: We now show each candidate's probability of reaching the second round (sum of all runoff scenarios where they appear), which is more meaningful than first-round leading odds.
Support trajectory over time
Estimated support over time for the top candidates. Lines show the mean estimate, shaded bands show 50% and 95% credible intervals. Dots represent individual polls.
Head-to-Head Probability
Probability that André Ventura leads Gouveia e Melo over time
Runoff Scenarios
With a second round nearly certain, these are the most likely candidate matchups based on our simulations.
Projected vote share
About this model
This forecast uses a Bayesian model that combines polling data with candidate-specific priors based on party affiliation. The model accounts for pollster house effects and uncertainty in voter preferences.
Note: Important: Approximately 35% of voters remain undecided. This forecast shows declared voting intention only - actual results may differ significantly as undecided voters make their choices.
Key factors in this forecast
- → Polling data from multiple sources
- → Candidate party affiliations and historical patterns
- → Pollster reliability and house effects
Model Assumptions
- • Forecasts DECLARED voters only (~65% of electorate)
- • ~35% undecided represent additional uncertainty
- • House effects informed by parliamentary election data
- • Random walk dynamics (Economist/538 methodology)
What do these uncertainty bands mean?
The shaded bands show the range where we expect true support to lie:
- • 80% credible interval: We're 80% confident the true value is in this range
- • Based on 8 polls and Bayesian statistical modeling
- • Wider bands = more uncertainty
- • Note: ~35% undecided voters add additional uncertainty not shown
About the presidential forecast
Portuguese presidential elections use a two-round system. If no candidate receives more than 50% of votes in the first round, the top two candidates proceed to a second round. This forecast models declared voting intention based on available polling data.
