A common complaint about presidential debates is that they change few minds.

This year, with anywhere between 3% and 6% of likely voters undecided in early September and the closeness of the race, especially in the battleground states, that is more than enough to swing an election if a sizable portion favor one candidate over the other as a result of the debate. If anyone doubts the power of a debate, the June 27 match between President Joe Biden and former president Donald Trump should end the argument, even though there are other examples to support a debate’s impact.

While the Biden-Trump debate did not affect the outcome of the 2024 election directly, it created doubts about Biden’s ability to serve another term and left us without historical precedent in the last 108 days of the race after Biden dropped out July 21. The entire campaign dynamic and Democrat ticket changed.

Since I was a graduate student in 1980, I have researched, observed, commented on, and written about presidential debates. I describe myself as a four-year cicada. My research consists of argument analysis, often applying statistical methods to sentence-by-sentence coding of arguments, focus groups of likely voters, surveys to gauge the impact of the debates on learning and leaning, and the ways the debate shapes future campaign arguments and strategies.

A summary of those findings makes the case for why it is important to watch the Sept. 10 debate between Trump and Vice President Kamala Harris, even if your mind is made up, and how you might consider watching and analyzing it yourself.

First, the question of who won or lost is the least important.

There is no single way to judge a debate, and “winning” does not guarantee winning an election as Walter Mondale in 1984, Michael Dukakis in 1988 and John Kerry in 2004 proved. Decided voters almost always think their candidate won. Rather, the debate should answer the questions “Who better represents the leadership qualities I want in a president?” and “Who better upholds the values I support?”

The debate showcases both issues and candidate image. That doesn’t mean that arguments and policy positions are not important, because they are. As hundreds of focus groups revealed, policies and issues candidates choose to discuss are windows into their priorities for the American people and their leadership style. A candidate’s conduct in the debate is a window into character for many voters, as focus group members in 2000 told us in response to Al Gore’s eye rolling and sighing at George W. Bush’s responses when he thought he wasn’t on camera.

They wondered how Gore would treat someone with whom he disagreed while in the Oval Office. Volumes were said about Trump’s interruptions in 2020, when focus group members of both parties were shocked by the behavior and friends emailed me that they sent their children out of the room lest they be influenced by the bad behavior.

Second, don’t expect much new information — but there are always unexpected questions and answers.

While this year is different because of the short time Harris has campaigned, most of her major positions have rolled out. On the other hand, we have not heard many details. Most candidates have campaigned for more than a year and participated in primary debates to lay out their agendas. Harris has not had that advantage. The debate needs to provide depth, but what history shows is that issues raised in debates are clarified and expanded on in the aftermath, even by long-term candidates.

Thus, watching a debate is more a first step for undecided voters than an event that seals the deal. Trump is an anomaly as a candidate, but everyone knows what they are getting in terms of leadership style and personality. In this election, he has changed positions more than in the past, and it is likely he will be asked to comment on the shifts.

Third, there are multiple agendas operating in a debate and not all are well-served.

The news media represented by the moderators have an agenda, each candidate has one, and the public has issues they want to hear about. Often the agendas don’t mesh, so don’t be surprised if the debate ends and you learned nothing about your top issue. It is likely there will only be one presidential debate and one vice presidential debate. With two-minute responses, two-minute rebuttals and an optional one-minute clarification, that is not enough time for depth on anything and also not enough time to cover everything. As a result, candidates often will briefly answer a question and raise an issue of their own in the same response. It’s frustrating for voters, but candidates want to guarantee that their agenda is presented.

Without a town hall debate, the public’s agenda is missing from this election cycle, and it is up to the moderators and the candidates to be aware of what the public considers the top issues and address them. Realistically, with the format, that may not happen. Without an opening statement to set the stage, the questions become a random set of arguments that may or may not lead to a coherent view of each candidate’s overall platform.

This leaves the closing statement to address each candidate’s agenda and relate it to the public’s. If it doesn’t, those undecided voters walk away still undecided. If you are one of those undecided voters, you need to do some work on your own to fill in gaps by searching a wide variety of news sources after the debates — and ignore the campaign’s spin doctors. Look at candidates’ websites, find major speeches on YouTube or TV network websites and find the answers you need.

The debate is a starting point for comparisons this year, not the end point of the race.

Fourth, expect both candidates to make erroneous statements.

Some of them are intentional and some are slips, which can happen given the number of topics and pressure of the debate. If the moderators don’t hold the candidates accountable through follow-up questions, be your own fact checker. Go to websites such as FactCheck.org, Snopes, PolitiFact, or ProPublica. A search of “top fact checking sites” provides others. Check out your candidate’s responses to prepare yourself to defend them if you engage in post-debate discussions.

Finally, watch the vice presidential debate because it may be the only other opportunity to compare the two tickets. Neither vice presidential candidate is that well known, and there is always a chance one of them will be president, as has happened nine times in our history. There may be issues covered that weren’t addressed in the presidential debate.

Focus groups often used the metaphor of a job interview to describe a debate. No one should get a job without one. As voters, we make the hiring decision, and it is important for us to watch the interview. On debate night, I will be at the Dole Institute of Politics in Lawrence, helping run DebateWatch groups comprised of students and community members. I expect to learn more about the power of debates to shape voters’ opinions of candidates and their choices.

The debate gives you power. So use it.

This commentary originally appeared in the Kansas Reflector, a States Newsroom affiliate.