Do presidential debates change voter preferences?

[keypoints]

• Limited effect: Studies show presidential debates rarely change the minds of most voters, with only about 3.5% switching preferences after watching.
• Name recognition: Debates help lesser-known candidates gain visibility, as seen with Barack Obama and John F. Kennedy.
• Undecided voters: Debates can influence undecided voters, helping around 7% of them make a final choice.

[/keypoints]

Do presidential debates change voter preferences?

Presidential debates have long been seen as crucial moments in election campaigns, but research and historical data show that their impact on voter preferences is often limited.

1. Limited Impact on Voter Preferences

Most studies indicate that debates do not significantly alter the outcome of elections. For example, a Harvard Business School study, which analysed debates in multiple countries, found little evidence that debates swayed voters in any notable way. Another study by Professors McKinney and Warner (2013) found that debates caused only a small percentage of viewers (3.5%) to switch preferences, while 86.3% of voters stuck with their initial choices after watching.

2. Debates Help with Name Recognition

While debates may not dramatically shift voter preferences, they are more useful for lesser-known candidates. In 2008, Barack Obama gained significant momentum after his first debate with John McCain. Similarly, in 1960, John F. Kennedy’s youthful and confident television presence helped him stand out against Richard Nixon, especially among those watching on TV.

3. Reinforcement for Undecided Voters

Debates can help undecided voters make a choice. About 7% of undecided voters made up their minds after watching debates between 2000 and 2012, as per McKinney and Warner’s study. This makes debates relevant for candidates hoping to win over the remaining undecided voters.

4. Historical Examples of Minimal Effect

In 2020, the debates between Trump and Joe Biden had little impact on the race. Polling data before and after the debates showed almost no movement, confirming that most voters had already made up their minds. Similarly, in the 2016 election, debates between Trump and Hillary Clinton produced minor shifts in polls, but not enough to change the overall trajectory.

5. 2024 Election: Kamala Harris vs. Donald Trump

As Kamala Harris and Donald Trump prepare for their 2024 debate, polling shows the race is tight. Historically, debates like this one do not tend to cause major swings in voter sentiment, but they could play a role for undecided voters or help candidates correct negative perceptions.

Conclusion

While presidential debates may not change election outcomes for the majority of voters, they can still play a role in swaying undecided voters, influencing perceptions of less familiar candidates, and reinforcing support among a candidate’s base. Their most significant effect tends to be in how candidates are perceived, especially in close races or when a candidate is relatively unknown.