Optimization is the science of making your work as effective as possible. You strategically tweak and test your landing pages, emails, and ads to maximize a specific metric, such as clicks, conversions, or opens.
And therein lies the problem with optimization: it can give you tunnel vision. Focusing too much on one metric can negatively impact others. That’s not to say you shouldn’t optimize your work (because you absolutely should). It just means that you need to think about metrics in relationship to each other, and consider how maximizing one might affect others.
When it comes to optimizing emails, one of the first things that comes to mind is usually subject lines and their potential affect on your open rate. The subject line is one of the easiest things to change, and it’s the first thing people see, so it’s going to have a big impact on whether or not people open your email, right?
But optimizing your subject line for opens can also negatively affect your click through rate. Here’s how.
Broad vs. specific subject lines
If all you’re worried about is open rates, it’s easy to find yourself writing the most broadly appealing subject lines that will appeal to the greatest chunk of your audience. The less narrow your focus, the more people your message appears to apply to.
This exposes more people to your content, but if your message only applies to a smaller percentage of your audience, your click-through rate (CTR) will probably stay about the same. The risk here is that a less focused subject line may not get as many opens from the right people.
Here’s what I mean.
Let’s say you have 1,000 people on your email list, but your offer is only relevant to 200 of them. With a highly specific subject line that makes it clear who you’re talking to, suppose all 200 of those people in your target open the email, and 40 of them click through to your offer. But since it was so focused, none of the other 800 people on your list open the email. So you have a 20 percent open rate, and a five percent CTR.
Then you optimize for opens, to expose more people to your offer.
So you make your subject line more broadly appealing, and everything else stays the same. Now you get 400 people to open your email, but since your subject line wasn’t as relevant to those 200 ideal members of your audience, only 100 of them opened it. So you have 300 people who opened your email who aren’t really interested in your offer, and only 100 who are. 20 people click through to your offer.
Now you have a 40 percent open rate and a 2.5 percent CTR.
Obviously these numbers and this situation are made up. But the point is, trying to appeal to a broader audience potentially means not appealing to as much of your target audience.
If your message is relevant to your entire audience, this isn’t something you need to worry about, but when you have a message that only applies to some of the people on your list, you probably want to make that clear in the subject line.
And of course, if you regularly send emails that only apply to part of your audience, you should probably make them into segments.
Changing your audience’s expectations
For newsletters and roundups, most people choose to use the most interesting tidbit as the hook in their subject line. Even if that section doesn’t take up the bulk of the email, this makes sense because that audience is used to sampling a variety of topics and stories. Even if they’re only reading your email to look for the section that addresses the subject line, it’s fine, because those emails are designed to be skimmable, often including links to a variety of pages or stories.
But try that approach to subject lines on an email that focuses on a single topic, and you might be disappointed by the resulting click-throughs. If you find an interesting hook, but your email barely addresses it, you’ll increase opens, but you’ll also create inappropriate expectations for what your email is actually about.
At its most extreme, this could mean using provocative subject lines that are wholly unrelated to your email’s content. Just because the subject line “Your free pizza” improves your open rate doesn’t mean it’s appropriate (or actually beneficial) when used for a product announcement.
If your opening copy doesn’t address the expectations established in your subject line, it feels like a bait and switch (or a mistake), and your audience is going to close your email before they even get to the call-to-action. So while your open rate goes up, your CTR goes down. What’s more, they’ll remember feeling misled and be less likely to trust your brand in the future.
This doesn’t mean you can’t use clever, creative subject lines. It just means that you need to come up with ones that align with the main purpose and content of your email.
Don’t fall for tunnel vision
Optimization is important. But when it comes to your bottom line, you can’t afford to only think about one metric. Each decision you make can potentially impact several metrics, and you need to pay attention to how those metrics work in relationship to one another.
Increasing one metric at the cost of lowering another isn’t always bad, either. At the end of the day, what really matters is that you wind up with more people clicking through your emails (or better yet, converting), and that you can continue doing that over the long run.
So as you A/B test your subject lines, audiences, and copy, be sure you’re paying attention to how your changes affect multiple metrics including your ultimate goal. Set goals, and test everything. Just don’t fall into the trap of tunnel vision.