• by Ray Schultz , Columnist, August 8, 2017

It could be argued that conversions are a better determinant of email success than opens. Viewed by themselves, open rates are a version of last-click metrics.  

Still, the open rate does measure interest in your content in a rudimentary way. So you may want to consider alternative ideas on how to conduct this analysis.

For example, George Beall argues in a post that “marketers should keep track of reopened emails in a separate metric when attempting to adjust their campaigns to increase email open rates in general.”

Reopened emails? Yes.

“Suppose a user clicks on an email and only spends a second on it, but realizes that there’s some important information in that email and then they go to reopen that same email to read more carefully,” Beall writes. “That’s a response that you’d want to be able to capture.”

Reopens are one of several things that can affect results. Another is whether the tracking method is valid.

In essence, opens are tracked in HTML emails with a tracking pixel — an invisible image that is displayed when the email is opened. When the recipient downloads it, the email is recorded as being opened, according to Beall.

“When we consider the rate, it is a fraction of the unique email opens divided by total emails sent unless the emails bounced,” Beall adds.

He continues: “In other words, it’s how many people saw your email in their inbox and had enough interest in the subject and title preview to click on it and check it.”  

Beall also advises you to measure the intervals. “For example, you might have trackers that download at different time intervals to measure how long the user has spent viewing the email since an open that is thirty seconds long is vastly different in quality than one which is less than a second,” he writes.

That last person might be “characteristic of someone just trying to get rid of all of the unread emails in their inbox and thus may misrepresent the actual interest by inflating the open rate,” he adds.

Here’s another way of looking at open rates, although it’s not exactly new: the “hidden metric,” the click-to-open rate, or CTOR.  

As Shamita Jayakumar notes: “It is calculated by the number of unique clicks divided by the number of unique opens.”

Before proceeding with his treatise on CTOR, Jayakumar offers handy definitions of the terms:

Open rate—The “percent of people emailed to who opened an email campaign. If you mailed to a list of 750 people and 180 of them opened, your open rate would be 24%, a nice average.

Click-through rate—The “percentage of people who clicked a link or any linked image within an email. 

So how do you measure CTOR?

“Using our ongoing example 100 clicks / 180 opens (multiplied by 100 for a percent) = 55%,” Jayakumar explains. “As with all other email metrics, this can fluctuate based on how awesome your content is.” 

Here’s why you should bother with this calculation:

“Because it’s based on the number of unique opens, CTOR is a good indicator of how interesting your content is to your subscribers,” Jayakumar says. “If your links, layout, copy and overall content are interesting, then your readers will want to click-through to learn more.

What’s a good CTOR? Oh, 20% to 30%. But Jayakumar argues that “for best results, with all of your email metrics, you’ll want to create your own benchmarks, not just go by the average numbers.”

Clearly, Beall is onto something when he says: “The measurement of email open rates may be more complex than you initially assume…”