Most Maligned Metric: A New Look at Open Rates

The open rate is one of the most cited, and yet derided, metrics in e-mail marketing. And both for good reason: On the surface it seems straightforward enough, but it’s impossible to measure accurately.

However, one expert has come up with a way to look at the lowly open rate that lends it new meaning.

“The open rate not only isn’t dead, it actually could give you some new and useful information,” says Deirdre Baird, chief executive of deliverability consultancy Pivotal Veracity. Though definitions vary slightly, Baird defines “open rate” as the number of individuals who open an e-mail divided by the net number of e-mails delivered after all bounces are subtracted.

Seems simple enough. But here’s the problem: An “open” registers when the receiving computer calls for a graphic from the sending computer. And as Internet service providers increasingly block images by default, some e-mail is getting opened and not registering as such.

At the same time, e-mail landing in boxes using so-called preview panes — those small windows that allow users a glimpse into their e-mail’s content — will register as having been opened whether the receiver read it or not. Baird also points out that many people check e-mail offline, such as on their personal digital assistant or on board a plane. None of those messages will give any indication as having been opened.

So clearly, anyone who thinks an “open rate” offers an accurate count of their opened e-mails is all wet.

“Unfortunately, you’re not going to be able to conclusively and comprehensively measure open rates,” says Baird. And so the metric is understandably widely criticized.

But that doesn’t mean it has no value. As Baird notes, “Open rates have merit in and of themselves simply [because] when there’s no preview pane they offer the ability to evaluate how compelling your ‘from’ and ‘subject’ lines are.”

Even though it can’t be pegged exactly, an open rate certainly can give marketers an idea of what people think of their brands. According to a recent survey by e-mail deliverability company Return Path, 55.9% of respondents cited knowing and trusting the sender as the main reason they’d open an e-mail.

In the same poll, 51.2% said the marketer’s previous behavior would influence whether they’d open an e-mail. That is, they’d opened an e-mail from the sender in the past and found it valuable.

“If nothing else,” Baird says, “the open rate is measuring if the combination of your ‘from’ and ‘subject’ lines is compelling enough to get people to open your e-mail, whether they’re finding it compelling because they know you and had a good experience with you in the past or because the subject line has something that’s nabbed your attention. In any given campaign, you’re not measuring [one or the other]. It’s a combination of those two things.”

Comparing the open rates of different file segments represented by the same inbox provider can be useful too, she adds. “For example, I would be very interested in finding out if there’s a difference in open rates for my high-value customers vs. my low-value customers at those ISPs where images are off. Because if there is, it indicates they’re doing something to ensure they see my images.”

Open rates can also signal when something is affecting e-mail at specific inbox providers. If a marketer’s open rate plummets only with Yahoo! addresses, Baird says, “something probably has happened at Yahoo! that [the marketer isn’t] aware of, and I would absolutely check there first.”