Welcome to FiveThirtyEight’s weekly politics chat. The transcript below has been lightly edited.

sarahf (Sarah Frostenson, politics editor): On Tuesday, Joe Biden launched his campaign’s first television ad of the 2020 cycle, leaning into his time spent as Barack Obama’s vice president and his performance in head-to-head polls against President Trump. And according to an ABC News analysis of TV ads, Biden is now the seventh Democratic presidential candidate to have run an ad so far. (The others: Julián Castro, John Delaney, Tulsi Gabbard, Kirsten Gillibrand, Kamala Harris and Tom Steyer.)

But, of course, the media landscape is changing, and many candidates are focusing on digital ad buys, too. So let’s talk about the role of ads in a presidential cycle — what is the role they play in mobilizing voters, and how do they help (or hurt) campaigns? And what role do we expect campaign ads to play here in 2020?

First up, though — let’s talk about that Biden ad and the other TV ads we’ve seen from candidates so far. What do we make of that Biden ad? It’s pretty similar to the video announcing his campaign launch in April, yes?

nrakich (Nathaniel Rakich, elections analyst): Yeah, like his launch video, he grounds the ad — and his reason for running — in the white-nationalist rally in Charlottesville, Virginia, in 2017.

He also very explicitly makes the point that he was Obama’s number two, and that is why people should vote for him.

ameliatd (Amelia Thomson-DeVeaux, senior writer): The new ad also focuses on Biden’s other big argument — that he’s the candidate best positioned to beat Trump. He goes there right away.

nrakich: Yep. The ad even has a graphic of several early general-election polls!

Of course, we at FiveThirtyEight know that those aren’t reliable predictors of what will actually happen in more than a year’s time.

meredithconroy: (Meredith Conroy, political science professor at California State University and FiveThirtyEight contributor): If I’m running for president (and I will, #Conroy2032), “strong, steady, stable” are words I want people to associate with me and my campaign. Those words are always relevant to presidential leadership, but they seem to be a core part of Biden’s strategy in the context of 2019, when Trump is president.

nrakich: Right, the ad yearns for the days when we had an administration “our kids could look up to” and calls Trump “an erratic, vicious, bullying president.”

sarahf: How does Biden’s first ad buy fit into the other ones we’ve seen? I know it’s early (only seven candidates have even made a TV ad buy), but what else is out there? I know Castro, for instance, released an ad after the shooting in El Paso that positioned himself against Trump, as well — but he struck a very different tone than Biden.

nrakich: I thought Castro’s ad was very strong.

He speaks directly to the camera about how the alleged gunman in the El Paso shooting used language similar to President Trump’s when writing about his motivations for the attack, and I think Castro comes across as a very effective messenger because he makes it so personal. He says people who “look like me, [who] look like my family” (i.e., Latinos) have come under attack during the Trump administration. And as Amelia wrote recently, many Latinos in the U.S. say things have gotten worse under Trump.

So for a candidate like Castro, who has struggled to get media attention, I think it was a smart move. He didn’t spend a lot of money on the ad ($2,775 according to NBC), yet many media outlets have written about it, so it probably had an outsized impact for what he spent.

meredithconroy: Right, unlike Biden, Castro has more room to build up his image since he is not as well known. And this ad suggests he wants to be known as someone who will go directly at Trump, especially when it comes to Trump’s impact on a community he cares about.

ameliatd: It was interesting strategically, too! It was a tiny ad buy like Nathaniel said, but it was during Fox and Friends. So he wasn’t just talking directly to Trump in the ad — he was actually trying to ensure Trump would see it.

It makes you wonder if other candidates will try to get free coverage by needling Trump with their ads.

sarahf: What about a candidate like Kamala Harris, though? She mentions Trump in her ad, but he definitely isn’t the focal point.

Structurally though, I thought it was kind of similar to Biden’s latest ad. The message is different, but it’s still introducing her to voters and letting them know what she’d fight for.

nrakich: Yeah, to me, Harris’s ad had the feel of a general-election ad. It’s very empathetic, and the policies it mentions (e.g., equal pay for women, a generic call for “Medicare for all”) are popular with the general public and extremely popular among Democrats.

That said, I found it less effective than Biden’s or Castro’s. Maybe the average voter won’t have this reaction, but to me, “3 a.m. agenda” is too close to Hillary Clinton’s “3 a.m. phone call” ad from 2008.

That ad had a very different message, though — instead of “what issues keep you up at 3 a.m.?” (a theme that I don’t think Harris’s ad communicates very well), it was “whom do you trust to pick up the phone when there’s a world crisis at 3 a.m.?”

ameliatd: I agree that the “3 a.m.” echo was unfortunate. But I’m not sure how many people will remember specifically that it was a Clinton ad.

Harris’s ad was striking to me because she highlighted the fact that she was raised by a single mother. So it was kind of similar to some of the very personal, sometimes viral ads we saw in 2018, like the one where Stacey Abrams talked about growing up without health insurance and living in debt.

meredithconroy: Harris has ground to make up, too. Her launch ad was short — less than a minute — and not biographical. And for the lesser-known candidates in the primary, it’s important that their ads introduce themselves, which Harris’s “3 a.m.” ad does. It’s biographical and touching, but it also informs her broader agenda — so a successful ad, in my opinion.

ameliatd: But isn’t that the opposite of what Castro did? And IMHO that ad was quite good.

meredithconroy: That’s why talking about campaign ad strategies is tough. A lot depends on the candidate and the moment. Harris and Castro have different things they need to accomplish, at this point. Castro needs to make the debate stage. Harris needs to win over supporters who may be backing another front-runner.

nrakich: Yes, Amelia, Castro’s ad was outside the box — which is why I think it was good. It stands out.

But also, I don’t know if it’s fair to call it his introductory ad (even though he hasn’t aired any others on TV). It was more like a sneak preview, haha.

sarahf: I do wonder, though, if going after Trump is a good overall strategy for campaign ads. Or whether positive ads where a candidate introduces himself or herself to voters is a better move?

What does the research tell us?

ameliatd: I think sometimes people assume that negative ads are more effective — but that’s not necessarily the case. Political science research has shown that attack ads and positive ads trigger different emotions (no surprise there) and that those ads lead to different kinds of reactions. So I think it’s really more about a candidate’s strategy and which voters they want to appeal to — do they want to be seen as someone inspiring? Or someone who can really go after Trump? There isn’t really a one-size-fits-all approach.

meredithconroy: The stage of the campaign where candidates announce they’re running is mostly over, though, so that means we’ll be moving away from more positive ads that seek to inspire, and toward more negative ads. And strategy-wise, ads that are negative may actually be good because research shows they are more memorable. One way to identify if the ad will be inspiring or negative is to listen to the music — research has also found that music and imagery are used to induce specific emotional reactions.

ameliatd: Meredith is right — these ads are so primal. It’s all about emotion. There has been research showing that just swapping out the music and imagery can change people’s reactions to advertisements.

nrakich: Yes, totally. The music, the colors and the narrator’s tone can all tell you within the first couple seconds if an ad is going to be negative or not.

ameliatd: So much for substance!

Except, that’s not really true. Studies have also shown that ads are actually a pretty effective way to inform voters about policy.

Hearts and minds, guys.

meredithconroy: ❤️🧠

sarahf: It is true that a lot of attention will be devoted to TV ad buys and the markets that candidates spend the most money in. But one other question I have is how are digital ads on, say, Facebook and Google, changing the landscape? Who’s leading there?

meredithconroy: Tom Steyer is leading there, Sarah! Is he running the best digital ads? I’m not sure. But he’s certainly spending the most on digital ads.

ameliatd: Right, he’s spent $2.9 million on Facebook ads alone. Which makes sense — he got into the race really late, he’s got a lot of money at his disposal as a billionaire, and he’s been trying to qualify for the debates.

meredithconroy: And it might be paying off. As of today, he is polling at 7 percent in early primary states, according to Morning Consult.

nrakich: Yeah, the split in that poll between Steyer’s standing in early states (7 percent) and nationally (1 percent) is really interesting.

He is also spending a ton on TV ads in the early states — probably smartly, as it is easier to move up in the polls in just one state. Early-state polls count for debate qualification too. In fact, all three of his debate-qualifying polls so far are from early states, not national polls.

sarahf: And Steyer needs to hit 2 percent in just one more qualifying poll by next Wednesday to make the debate stage, so I’m sure that’s a big factor in many of his ad purchases.

Although, when it comes to ad-buying strategy, it doesn’t seem as if Steyer has one. He’s invested heavily in both TV ads and online ads. He’s spent $3.6 million on digital ads, according to Bully Pulpit’s 2020 Campaign Tracker, and an estimated $6.2 million on seven TV ad buys, according to an ABC News analysis.

But I am curious, what does digital ad spending enable Steyer and other candidates to do differently than traditional TV ad buys?

ameliatd: The thing that’s been most helpful about digital ads, at least so far, is that you can target who’s seeing them. This is kind of the opposite of TV ads, which are blunter instruments. For example, if you’re trying to get people to donate small amounts to your campaign, digital ads could be the way to go.

meredithconroy: Right, there has been a move toward targeted digital advertising — “the equivalent of switching from a hacksaw to a scalpel.” That is something that candidates weren’t spending money on until 2008.

nrakich: That’s certainly true, but I think a hacksaw suits Steyer just fine, for now. In fact, I would argue that Steyer’s TV ads in early states have been more important than his online spending.

ameliatd: What makes you say that, Nathaniel?

nrakich: Well, first of all, as Sarah mentioned, he has spent more than $6 million on TV ads, primarily in media markets that cover Iowa, New Hampshire, Nevada, and South Carolina. That’s nearly twice as much as he has spent on digital ads.

Second, a plurality of Americans (49 percent) still get their news from television. And more Americans watch TV than are on Facebook. A full 97 percent of American households used a TV in 2015, while “only” 69 percent of Americans have a Facebook account, as of 2019.

meredithconroy: Yes, broadcast is still king/queen. But that will probably change, maybe even by the next presidential cycle. For instance, from 2014 to 2018, the share of political ads on TV dropped while digital advertising rose. However, this doesn’t mean that candidates won’t still spend more on broadcast than digital (at least right now).

ameliatd: For sure — candidates always spend a lot more on TV than on digital. But it’s been interesting to see how the debate rules appear to have affected some Democrats’ digital advertising, which means the focus might shift there, too.

sarahf: Yeah, let’s talk a bit about how the debate rules might be changing how candidates approach digital advertising. We don’t have any hard numbers on what percentage of ads bought online were used for fundraising purposes, but the small donor requirements for the first three debates has meant that candidates have had to step up advertising (largely online) to attract donors, right?

ameliatd: The Washington Post did an analysis of Facebook ad spending data in June that found that about a quarter of the campaigns’ ad spending was explicitly focused on the debates. That’s a lot.

meredithconroy: And after Steyer, Gillibrand has spent the most on Facebook ads among the Democratic field — $1.1 million. Gillbrand still hasn’t met either the donor or polling requirements to make the third debate, so she’s using Facebook (and Twitter) to solicit donations.

sarahf: What about a candidate like Elizabeth Warren, who has eschewed the traditional TV ad blitz for an online-first approach where her team produces many of their own ads? Is this the future of campaigns?

nrakich: I’m old enough to remember that digital ads were considered “the future of campaigns” back in the 2012 cycle, too. But it hasn’t happened yet.

I agree that they are an important part of any modern campaign ad plan. But I’m not sure they’ll keep growing ad infinitum to the point where they supplant TV.

ameliatd: Increasingly, I think it has to be a “both, and” strategy, right? Lots of Americans watch TV. But TV ads are expensive, and you can’t micro-target your ads to reach specific people. Not to mention, online ads certainly allow for more creativity — for one thing, they can be much longer than TV ads.

But in a lot of ways, politics is still pretty analog. An analysis of Democrats’ advertising in 2018 showed that direct-mail campaigns were still one of the biggest expenses.

meredithconroy: And don’t forget YARD SIGNS!!

sarahf: I don’t know. I think digital ads are going to play an important role here in 2020. After all, part of Trump’s 2016 mojo that he’d like to replicate in 2020 was the success he had with Facebook ads. He outpaced Hillary Clinton in digital ad spending in 2016 and is currently outpacing Democratic candidates in Facebook ad buys — he’s already spent $9.6 million there. So I think it’s possible to have a smart digital ad strategy.

ameliatd: My sense, also, is that Facebook ads are good for raising money. Probably also good for mobilizing/exciting voters.

Another thing working in Facebook’s favor is that if you have a bunch of small, cheap ads, you can do a lot of testing — see what works for different audiences. That’s not really something you can do with TV.

nrakich: There is also a belief in campaign world (whether it has hard evidence behind it, I dunno) that people are more likely to listen, and potentially be persuaded, if they are getting a campaign message from someone they know and trust. (For example, a friend or family member.)

This is one reason why I think Warren’s “selfie strategy” of spending hours after her rallies taking selfies with individual people is really smart. Because what happens to those selfies? People post them on their Facebook pages, and their friends get the implicit (or perhaps explicit, depending on the caption!) message that Jane Q. Voter endorses Warren. And I think that’s powerful stuff.

ameliatd: I think you’re right, Nathaniel. Warren has been smart about how she’s engaged with her supporters. For a while she was also calling donors personally to thank them, which people then posted about online.

But, that and the selfies take time.

nrakich: Yeah, but I’m open to the argument that they’re a good use of time.

meredithconroy: I am too.

nrakich: Plus, she doesn’t dial for dollars or go to high-dollar fundraising events, so this just takes the place of those staples of traditional campaigning.

ameliatd: I’m not saying it’s not a good use of her time! It’s just interesting to see candidates making these choices and trade-offs. The combination of a huge field + lots of ways to reach voters means that there’s a lot of experimentation. Which, to nerds like us, is cool.

sarahf: OK, so it’s early yet, and there are still many more ads we haven’t yet seen, but who, at this point, is running the best campaign ads? Or, if there isn’t one candidate who stands out to you, what approach to campaign ad buys do you think will be effective in 2020?

I, for one, am pretty convinced that Facebook ads will continue to play a big role (coupled with Google ad buys) just given the success Trump had in 2016. I also think that Biden’s ad strategy isn’t that bad. He’s running on the idea that he’s the only candidate who can defeat Trump and his ads (so far) have reinforced that idea — so he’s staying #onbrand, which when you’re running for president isn’t a bad thing.

nrakich: I think Steyer’s ad strategy has obviously been the most effective so far. He is the only candidate whose ads appear to have moved the polling needle. But that might be because he is the only candidate who has put real muscle behind his ad campaign, not because the ads are intrinsically good. I want to wait until other people’s ad campaigns get more robust.

And, of course, we have to see if Steyer is able to sustain his advertising pace. Getting a nice polling bump in August doesn’t matter if it fades by October.

ameliatd: Right, I’ve seen research showing that the effects of political ads wear off pretty quickly. So that’ll be an important question for Steyer moving forward. But which ads to run, and where, is also an increasingly high-stakes consideration for lower-tier candidates — if they’re spending a lot of money but still not breaking through, how can they get the most bang for their buck?

meredithconroy: Political science research does suggest that candidates do better in counties where they spend more than their opponents. So saturation is not a bad strategy, but Amelia’s right, the effects of ads decay over time.

But figuring out the best advertising strategy is complicated by the large Democratic field. We have a relatively new advertising landscape, with more platforms for content production, sharing and micro-targeting. So it is difficult for campaigns to know exactly what is working. But perhaps following Trump’s 2016 campaign, which experimented with its advertising strategy and by most accounts did so with success, Democrats may continue to experiment, while also still relying on more traditional forms of advertisements.