Latest / The Copywriting Podcast with Fexingo: Sales Letters, Headlines, and Persuasive Writing / How a Dash Replaced a Comma and Tripled Response
Transcript
- Lucas: So there's this 1963 fundraising letter from the American Cancer Society — a classic in direct mail history. It was pulling a solid response, around 2.8 percent, which was decent for the time. Luna: A control package, basically. Lucas: Exactly. And the copy chief — a guy named John Caples, you might've heard of him — looked at the letter and decided to change one thing. Just one punctuation mark. He swapped a comma for an em dash in the closing paragraph. Luna: And that tripled response? I've seen this stat floating around, but I want the real numbers. Lucas: From 2.8 percent to 8.7 percent. Over three times the original. The letter went from pulling about 28 donations per thousand to 87 per thousand. On a national mailing, that's hundreds of thousands of dollars — in 1963 money. Luna: Okay, I'm hooked. Walk me through the exact sentence. What was the before and after? Lucas: The original read, 'Won't you please send a generous contribution now, so that we can continue our vital research.' Standard comma before the 'so' clause. Caples changed it to: 'Won't you please send a generous contribution now — so that we can continue our vital research.' That's it. Comma to em dash. Luna: And that tiny shift tripled the response? I mean, I believe the data, but it feels almost magical. Lucas: It's not magic — it's psychology. The comma is a soft pause. It signals a continuation, like the sentence is still in motion. The em dash is a dramatic break. It forces the reader to stop, reframe, and then receive the reason with fresh emphasis. You can almost hear the voice change: 'Send money now — pause — here's why.' Luna: That makes sense. The dash gives the reason its own stage. It's not just tacked on. Lucas: Right. And this principle — punctuation as emotional cue — is something a lot of modern copywriters have forgotten, or never learned. We obsess over words, but the pauses between words carry just as much weight. Luna: Speaking of modern applications, I saw a SaaS landing page last week that did something similar. It was a project management tool — their hero headline was: 'Stop juggling spreadsheets — and start shipping projects on time.' With a dash. And I remember thinking, that reads differently than if it had a comma. Lucas: Exactly. Comma would be 'Stop juggling spreadsheets, and start shipping projects on time.' That sounds like a single continuous thought. The dash splits it into two commands: stop this — then start that. More urgent. More actionable. Did you happen to see their conversion numbers? Luna: I actually looked it up. They A/B tested the dash vs. the comma. The version with the dash had a 17 percent higher trial sign-up rate. Not triple, but significant for a landing page. Lucas: It's consistent with the principle. The dash creates a pause that reframes the second half as the payoff. Now, the reason it didn't triple here is context — the American Cancer Society letter was asking for a donation, which is a high-friction ask. A trial sign-up is lower friction, so the emotional leverage is smaller. But the mechanism is the same. Luna: That's a great point. The higher the friction, the more a dramatic pause can tip the scale. So for a charity appeal or a big purchase, dashes might be more powerful than for a free trial. Lucas: Exactly. And by the way, if these copywriting conversations have sparked something you've actually used in your own writing — maybe a tweak that worked — it's worth mentioning that listener support is what keeps this show ad-free. A couple of dollars a month at buy me a coffee dot com slash fexingo genuinely makes a difference. No pressure, just if you've gotten value from it. Luna: Yeah, and honestly, that dash trick alone might've earned back the coffee cost for someone who tested it. I've seen it work. Lucas: Alright, back to the dash. The other thing Caples noticed was that the dash changed the rhythm of the sentence. In direct response copy, you want the reader to keep reading — but you also want them to stop and feel the ask. The comma doesn't force that stop. The dash does. Luna: What about multiple dashes? I sometimes see copy with three or four dashes in a paragraph. Does that dilute the effect? Lucas: It can. The dash works because it's a deviation from the norm. If every sentence has one, it becomes the norm. You lose the dramatic tension. In Caples's letter, that was the only dash in the entire copy. That's part of why it hit so hard. Luna: So it's about scarcity. Use the dash sparingly, and only at the most critical moments. Lucas: Precisely. And that applies to other punctuation too — ellipses, parentheses, even semicolons. Each one has a different emotional weight. Semicolons, for instance, feel intellectual, connected. Parentheses feel like an aside, a whisper. Ellipses feel like trailing off, uncertainty. Luna: I've seen ellipses overused in nonprofit emails. 'We need your help... to save the children.' It often feels manipulative. Lucas: That's because the ellipses signals hesitation, which can undermine urgency. The dash, on the other hand, signals conviction. It's a confident break. 'We need your help — now.' That's a punch. 'We need your help... now.' That's a sigh. Luna: Right. And the dash doesn't have to be just one hyphen. In print, it's longer — the em dash. But in digital copy, most people just use two hyphens. Does that matter? Lucas: In terms of visual impact, yes. An em dash is a single long line, which feels more deliberate. Two hyphens look like a shortcut. But for most online readers, they won't consciously notice. The effect on the reading rhythm is the same because the brain still interprets it as a pause. So if you're writing for the web, two hyphens are fine. If you're writing for print, use the actual character. Luna: What about the en dash? That's shorter, used for ranges. Lucas: En dash is for numbers, like '1990–2000.' It doesn't carry the same rhetorical weight. Stick with the em dash for dramatic pauses. Also, avoid spaces around the dash — some style guides say to use them, but in copywriting, the no-space version reads as a single breath. 'Now—so that' feels tighter than 'now — so that'. Luna: I want to go back to the American Cancer Society letter. Do we know the full context? Like, was it a one-page letter or a multi-page package? Lucas: It was a two-page letter with a reply envelope. Standard fare for the era. The dash appeared in the last paragraph, after a long build-up about the research and the need. So the reader had been led through a narrative, and then hit that dash. It was the climax. Luna: That makes sense. The dash works best at the moment of the ask. If you put it earlier, it might undercut the buildup. Lucas: Exactly. And that's the lesson for today: think of punctuation as stage direction. The comma tells the reader to keep walking. The dash tells them to stop and look. Use it on the most important line — the one where you want them to act. Luna: So before you hit send on that next email or publish that landing page, scan it for commas in the call to action area. Ask yourself: should that be a dash? Lucas: That's a solid takeaway. And if you test it, let us know what happens. I'm curious how many people see a lift, even if it's not a triple. Luna: Yeah, I'd love to see a modern replication of Caples's test. Someone should run a proper A/B test with a charity email and a dash vs. comma in the ask line. Lucas: If anyone does, we'll cover it. Until then, keep your dashes sharp and your commas in check. That's it for this episode.