Runoffs

Runoffs are secondary elections held when no candidate achieves a required threshold in an initial contest. In politics, runoffs are used to ensure that the winner has broad support, typically a majority of votes.

Most commonly, a two-round system is used: if no candidate reaches the required threshold in the first round, a second round is held between the top finishers. The threshold is often a majority (more than 50%), though some jurisdictions set a different minimum. Runoffs can apply to general elections or to party primaries that nominate a candidate for the general election. In practice, the second round concentrates political campaigns and can change the outcome due to vote transfers and turnout differences. Turnout in runoffs is often lower than in the first round, and the process adds cost and administrative complexity. Some places have replaced runoffs with instant-runoff or ranked-choice voting, which seeks to determine a winner in a single election by transferring votes according to voters’ preferences.

Examples include the United States state of Georgia, where a runoff is held if no candidate reaches 50 percent in the general election, and Louisiana, which uses a jungle primary with a runoff for statewide and many local offices.

In hydrology, runoff refers to rainwater that flows over the land surface to streams and rivers, rather than infiltrating the soil. It is influenced by rainfall intensity, soil saturation, land cover, and topography and is a key component of watershed dynamics.