Copywriter vs. AI: Who writes stronger sales email subject lines?

Can AI write subject lines as good as (or better than) what an experienced conversion copywriter can write?

Let’s find out.

In this video, I walk you through the results of this copywriter vs. AI experiment.


Can AI write subject lines that are as good as what an experienced conversion copywriter could write?

Hi, I’m Paige from The Impact Copywriter. And I help founders and marketers boost the conversion rates for their most critical campaigns by focusing specifically on their marketing messages, or as we like to call it, the copy.

As a copywriter, I also wonder if AI is going to be my competitor or my collaborator. So recently, I put AI to the test. I ran an experiment to see if AI could generate quality subject lines for the sales emails I was writing.

Let’s look at the results.

Here’s the situation. I was optimizing some sales emails for a client. I was at the point of the project where I already had solid drafts of all the emails, and now it was time to write subject lines.

I try to push myself to write at least 15 subject lines per email before going through them and actually choosing which two subject lines I’m going to propose for A/B testing during delivery.

Now that I’m experimenting with AI I thought: Could AI help me write subject lines? And what would that look like? Would they be any good? What would that whole experience be like?

So let’s see.

I’m using Open AI. And my prompt for the AI was: Write 15 email subject lines using copywriting formulas for this email. Then I copy and pasted the specific email into the chat. It took all of 30 seconds-ish to a minute for it to generate 15 subject lines.

I will highlight that I have I’ve done this a few times. So this wasn’t my first experiment. I had done a few before this, and I’ve been playing around with what to ask the AI.

For this question or this prompt or command, I guess you could say, I did add “using copywriting formulas” because when I don’t, when I just say write 15 email subject lines for this email, there is a bit of a difference. They are a little bit better from a copywriting standpoint when I add the “using copywriting formulas.”

Then I experimented with asking the AI if it could rewrite the subject lines it just wrote to create more curiosity just to see what would happen. If you pause the video and look at the differences, the way it created more curiosity mostly was just adding secret, surprising solution, you won’t believe it, and so on. That’s kind of how it’s solved for adding curiosity. I just thought that was interesting.

Let’s go back to the original subject lines. As you can see from a copywriting standpoint, these aren’t great. As a trained conversion copywriter, I would evaluate these as surface level, vague, at least most of them, surface level, vague statements that we would start with but we would want to push further for a compelling subject line.

These are subject lines that I would consider to be easily ignorable in the inbox, most of them, because they’re not specific enough. They’re not really relying on the range of copywriting formulas that we have in copywriting, for example like using a testimonial-type subject line where you put things in quotation marks.

(I mean these are all in quotation marks, but it generates them that way. It’s not because they’re like pretending to be a testimonial or indicating that they’re a testimonial.)

There’s a lack of specificity. If you look here at “real member savings,” we would be want to be more specific.

After doing this little AI experiment and getting some ideas, I started my own brainstorming.

Because obviously as a trained conversion copywriter, I can look at the subject lines that the AI gave me and say these are not good enough. It just became a like a jumping off point for me to start generating new ideas.

You can see here what I came up with by pulling ideas from the email had already written, pushing those ideas further, and relying on a more diverse range of conversion copywriting formulas.

If you pause the video and compare them, you can see that the second list creates more curiosity. It’s more specific.

For example, “Tim saves 60 a month on equipment insurance,” that was literally in the email. It was the headline of the email, but the AI actually took all those testimonials and kind of grouped them together in a really general statement. It said, you know, “real member testimonials,” which isn’t as catchy as looking at how much money someone actually saved.

Or for example, saying something like “affordable insurance for photographers” and then I actually knew to push that further. What is affordable? So I wrote one that said up to 15K in equipment coverage for $0.79 cents a day. So it’s a lot more specific.

All in all, the subject lines the AI generated, they’re not bad. Right?

They’re a good starting point, especially if you don’t write copy. You could run with these, of course, I would consider putting them into sentence case and not title case, but you can consider running with these or some version of these if you don’t know anything about copywriting formulas. And you would get some opens. I would expect that you would get some opens.

But you can see that I was able, as a conversion copywriter, to actually push ideas further, rely on a more diverse range of copyrighting formulas, and pull in things from the VOC research. I was able to evaluate subject lines and say: Well, this is too vague or this is too boring. This needs to be more specific.

I was also able to look at the subject lines generated and, knowing the strategy for the emails, be able to evaluate which subject lines actually match the stage of awareness that our email was set up for.

So: Did the AI produce email subject lines that were as good as a conversion copywriter can produce?

I would argue: no. But, of course, we would always want to test them against each other.

If you want to stand out in the inbox, I believe the human copywriter’s creative capacity is going to be the thing that sets you apart.

Here’s what I think: AI might be a huge help when it comes to writing short blog posts or social media captions. But can AI help you with your sales pages and emails? I’m not convinced, not yet anyway, which is good news for copywriters everywhere.

If you need help running higher-converting campaigns that have a human copyrighter’s creative touch, let’s chat. You can start a project conversation with me right here.

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