Lula went from trailing by 2,224,965 votes in round 1 to winning the runoff by 4,430,191. The official totals show how the margin moved, but not why people voted the way they did. Below are eleven possible explanations, each rated by how much evidence backs it.
Change in the vote margin
+10,376,694more votes for Lula in the runoff than in round 1
+3,721,538more votes for Flávio
14,098,232increase in the finalists’ combined total (net)
6,655,156change in the margin: Flávio +2,224,965 → Lula +4,430,191
Round-1 votes for eliminated candidates 9,316,747Net rise in turnout 2,960,239Fewer blank and null ballots 1,821,246
9,316,747 + 2,960,239 + 1,821,246 = 14,098,232. These are net totals, not three groups of people. Some voters showed up, some stayed home and some switched, and those moves partly cancel out. Lula’s 73.6% is simply 10,376,694 ÷ 14,098,232.
Evidence by explanation
Data and research
Available dataBallot records and logsTSE ballot data can support section-level studies; aggregates do not reveal individual trajectories.
No confirmed deadlineLog coverageReconcile post-17:00 analyses and document coverage and timestamps.
Evidence neededPanel or post-election surveyAsk about participation and vote choice in both rounds, allowing for recall and nonresponse error.
Further researchCausal studiesStudies that test specific explanations against each other. None has a release date yet.