An October surprise is an event that could shake up an election, but does it often make the difference?Matt Dallek, a professor of political management at George Washington University, described it as "an event that, at least in theory, has the potential to shake up an election, something that people did not foresee coming that upends the debate."He said the term dates back to around the 1980 election, when President Jimmy Carter failed to secure the release of American hostages being held in Iran before November 4, 1980, election day.

Carter lost to Republican rival Ronald Reagan.

Several surprises have occurred in the years since.