Latest / The Copywriting Podcast with Fexingo: Sales Letters, Headlines, and Persuasive Writing / How a P.S. Lifts Conversion by 42 Percent
Transcript
- Lucas: So we've talked about headlines. We've talked about subject lines. We've talked about the body of a sales letter. But there's one piece of real estate in every piece of direct response copy that almost always outperforms its size. Luna: Let me guess — the P.S.? Lucas: Exactly. The postscript. And I want to start with a number that still blows my mind. In one of John Caples' classic direct mail tests, adding a single sentence to the P.S. lifted response by 42 percent. Not 4 percent. Forty-two. Luna: That's massive. What was the sentence? Lucas: It was something like: 'P.S. If you order within the next 10 days, you'll also receive a free bonus report.' Urgency plus a bonus. But it wasn't even a new offer — that bonus was already mentioned inside the letter. The P.S. just repackaged it. Luna: So the P.S. is basically a second headline. Lucas: That's exactly how Caples thought of it. He said the P.S. is the second-most-read part of any letter, after the headline. Because readers scan. They look at the headline, then they flip to the bottom to see who it's from and what the deal is. The P.S. catches that eye movement. Luna: I've definitely done that. I open a mailer, glance at the headline, then immediately skip to the bottom to see the offer and the signature. Lucas: Right. And that's why the classic sales letter formula always includes a P.S. — sometimes two or three. David Ogilvy said the P.S. is one of the most effective ad elements ever invented. He'd put a P.S. in every piece of copy he wrote. Luna: Let's talk about what makes a good P.S. today. Because email is different from direct mail. In a preview pane, the P.S. might not even be visible. Lucas: True. But the principle still holds. In email, the P.S. is often placed below the signature — and studies show readership is still high. A 2022 eye-tracking study by the email platform Mailchimp found that the post-signature area in emails had a 63 percent gaze rate among readers who scrolled past the main body. Luna: So even in a digital format, people look at it. What are the best uses for a P.S. in 2026? Lucas: I'd say three main plays. One: recap the core offer and the key benefit. Two: add urgency — a deadline, a limited quantity. Three: include a testimonial or social proof that reinforces the decision. Luna: Give me a real example. Not John Caples — something from this decade. Lucas: Sure. There's a travel subscription company called Pack Up + Go. They send an email every month promoting their surprise trips. Their standard P.S. is something like: 'P.S. Our next booking window closes Friday at midnight. Last month we sold out in 72 hours.' That's urgency plus social proof. Luna: And I'm guessing they tested it. Lucas: They did. They A/B tested a version with no P.S. against a version with that one. The P.S. version increased click-through rate by 21 percent and conversions by 14 percent. Not quite Caples' 42 percent, but still a big win for a single sentence. Luna: What about the risk of making the P.S. too long? I've seen emails where the P.S. is half the letter. Lucas: That's a mistake. A P.S. should be one to three sentences max. If you need more, you're rewriting your main copy. The P.S. is a highlight reel, not a second act. Luna: So keep it tight. What about multiple P.S.'s? You mentioned some letters have two or three. Lucas: That's a technique from long-form direct mail. You'll see 'P.S.... P.P.S.... P.P.P.S.' Each one adds a new piece of information. But in email, more than one looks cluttered. Stick to one P.S. — unless you're doing a very long sales letter by email, which is rare now. Luna: I want to push back a little. Doesn't the P.S. feel gimmicky? If every sales letter has one, aren't readers numb to it? Lucas: That's a fair question. And the answer is: only if the P.S. is weak. If it just repeats the headline, it's wasted. But if it adds something — a new testimonial, a specific deadline, a bonus — it's not gimmicky; it's useful. Readers are smart. They know why it's there. They're looking for the most important information. Luna: So it's not about tricking anyone. It's about serving the skimmer. Lucas: Exactly. The skimmer is your best friend in copywriting. They're busy. They want the offer fast. The P.S. is your chance to give it to them before they hit delete. Luna: Let's talk about a specific structure. If I'm writing a P.S. today for an email, what's the formula? Lucas: I'd say: 'P.S. plus.' For example: 'P.S. This course normally costs $297, but you can enroll today for $197. This price ends Sunday.' Or: 'P.S. Over 1,200 marketers have already joined the waitlist. Don't miss your spot.' Luna: What about a P.S. that's a question? I've seen: 'P.S. Ready to double your conversion rate? Click here.' Lucas: That works too. It's a direct call to action. But I'd pair it with a benefit. So: 'P.S. Ready to double your conversion rate? Our clients see an average 112 percent increase in the first month. Click here to start.' Luna: Right, give the proof. Let's go back to that Caples test. Forty-two percent lift from one sentence. Do you think that kind of result is replicable today? Lucas: I think the magnitude is rare because direct mail response rates were different — lower baseline, so a change looks bigger. But the principle is absolutely replicable. In fact, a lot of email marketers I talk to say the P.S. is their highest-performing element in A/B tests. Luna: Do you have a recent number? Lucas: Yeah. The email consultant Andrei Mincov ran a test for a SaaS client last year. The control had no P.S. The variant had a simple P.S. that said: 'P.S. If you sign up today, you'll get free onboarding — a $500 value.' The variant lifted conversions by 18 percent. Not 42, but still significant. Luna: And that's a freebie in the P.S. that was already in the body copy? Lucas: Exactly. It was mentioned in the main text, but the P.S. highlighted it. Reminding people works. Luna: Okay, so we've covered the what and the why. What's the one thing you want listeners to take away from this episode? Lucas: Always include a P.S. in your sales copy — email, direct mail, even landing pages if you can. But don't just tack it on. Treat it as a strategic element. Ask yourself: what's the one thing a skimmer absolutely needs to know? Put that in the P.S. Luna: And test it. Even a small change can have an outsized impact. Lucas: Right. Test one P.S. against another. Test a P.S. with urgency against one with a testimonial. The data will tell you what your audience responds to. That's the real lesson from John Caples: he tested everything. Luna: So next time I write an email, I'm spending as much time on the P.S. as on the subject line. Lucas: That is exactly the right instinct. Because the subject line gets the open. The P.S. gets the click.