Most click-through data is wrong, and here's why

Like all things, measuring email effectiveness means picking the right metrics. According to research from Demand Metric and Return Path, poorly defined metrics are a major challenge for marketers. Many teams default to high-level indicators like open rate and click-through rate (CTR).

Open rate helps you assess subject lines and body copy. For inboxes like Gmail and Apple Mail, it also tells you how your company logo renders. Both matter when you're trying to understand what's working.

CTR is how you judge whether your email content is actually persuading people to act. That's the whole point of an email: get the reader to do something. The problem is that most teams calculate CTR in a way that produces a number, not an insight.

Why your click-through rate is probably misleading you

The most common CTR formula is also the most misleading one.

Only recipients who open your message can click. Full stop. Including non-openers in your email click-through rate calculation doesn't make the number more accurate. It makes it less useful.

How marketers incorrectly calculate unique click-through rate

Unique recipients who clicked ÷ Total recipients

Here's what that looks like in practice. A client ran a re-engagement campaign to a list of more than 100,000 contacts, targeting people who hadn't opened an email in 18 months. Only 1,423 recipients opened the first message. The campaign performed well, but the CTR math didn't reflect that.

Dividing clicks by total recipients produced a CTR of 0.334%. Technically correct. But does that number tell you anything meaningful about content performance when only 1,423 people ever saw the message?

It doesn't. And if you're making decisions based on that number, you're flying blind.

How to calculate a true click-through rate

When you evaluate email content, ask yourself: if a recipient didn't open the message, should they factor into your CTR at all? The answer is no. Non-openers belong in your email deliverability metrics analysis, not your content performance calculation.

The formula is straightforward:

True unique click-through rate

Unique recipients who clicked ÷ Unique recipients who opened

Using the same example above, the client's true click-through rate was 25.2%. Benchmarks vary by audience and campaign type, but that's a strong result for any re-engagement send. The content was working. The old formula just hid it.

Why the difference matters for decisions

Say you send a prospect newsletter to 100,000 people.

Using the traditional method (clicks ÷ sends), you might see 3.1%, 2.9%, 3.2%, 3.5% month to month. Was the first email really 0.2% better than the second? There's no way to know.

Now calculate CTR as clicks ÷ opens. You might see 23.4%, 19.5%, 27.3%, 33.3%. The picture becomes clearer. The last email performed at least 21% higher than the rest. Now you have a number you can act on, not just report.

"I find this method not only a great way to quantify our program successes," said Brandon Palmer, digital marketing specialist at Access Marketing Company, "but also a great starting point when digging deeper into what caused the increase in engagement."

What accurate CTR data lets you do

Once you're working with a CTR that reflects actual email content performance analysis, you can:

• Assess email effectiveness accurately: know whether your copy, offer, and calls to action are doing their job
• Identify what needs attention: spot underperforming campaigns without false positives from list size
• Segment with confidence: group recipients by real email engagement segmentation and send messages you know resonate

The goal isn't a better-looking dashboard. It's knowing which emails are worth repeating and which ones need rethinking, without having to dig through a spreadsheet or ask someone to pull the numbers for you.