Unique opens vs total opens: what’s the difference, and why does it matter?
by Stu Elmes
4 minutes read time | 15 May 2019
Seeing a healthy, robust email open rate when tracking the performance of an email marketing campaign is a great feeling.
For an email marketer, there’s no higher praise for email subject line prowess.
And we should know. Here at Phrasee, we’ve tracked the open rate performance of millions of email subject lines across dozens of industries and thousands of campaigns. It’s a huge part of what we do.
There’s something important we learned very early on in this process, something everyone tracking subject line performance and open rates should take note of…
Not all opens are created equal.
In the world of email open rates there are opens, and then there are “opens”. Knowing the difference can (and often does) mean the difference between gathering meaningful data that successfully optimizes email subject line performance and meaningless data that optimizes very little at all.
Tracking the total opens an email campaign generates can be helpful, but tracking the unique opens is where the subject line optimization money is.
What’s the difference between total opens and unique opens?
Total opens are calculated by tracking the total number of times an email is opened, regardless of how many individual subscribers those opens are generated by.
– One email. One open. One “total open”.
Unique opens, on the other hand, are calculated by counting the first time a single subscriber opens an email. All subsequent opens from that subscriber are ignored.
– One email. One recipient. One open. One “unique open”.
The difference is a subtle but important one.
Why would a single subscriber open the same email multiple times?
As strange as it may sound, a single subscriber generating multiple opens of the same marketing email is actually quite common. There are a few reasons for this:
1. The subscriber forwards your email to someone else, who then opens it (this is a good thing!)
2. The subscriber opens your email, likes what they see, and returns to open the email again later to follow up (this is also a good thing!)
3. The email client counts an open, every time the subscriber scrolls through their inbox.
4. Some sort of bot is associated with the email client, or is being used by the recipient’s domain (this can be part of a company’s IT security infrastructure). When this happens, a bot is used to click each link within the email, to alert companies to potential phishing scams.
Why does it matter?
When it comes to optimizing a brand’s email subject lines to maximize opens, performance data is crucial. It is simply the only tool we email marketers have to gain insights into what subject line language works on our audience and what subject line language doesn’t.
While on the surface the arguments for counting multiple opens from the same recipient—forwards and returning readers (some of which result in actual sales)—might seem to outweigh the risk of those multiple opens coming from bots or agents, the truth is actually quite the opposite. The reason for this is simple: it’s a matter of scale.
A few forwarded emails and a handful of returning readers here or there generally have a very small impact on the total number of opens a campaign will generate. When dealing with bots or agents, which are capable of opening an email a thousand times in a relatively short period, the impact on campaign performance metrics can be significant.
OK, now what?
With bots at the helm, a small number of accounts can often be responsible for a disproportionate number of total opens. That would be great if they were also responsible for a disproportionate number of sales.
Sadly, they aren’t.
That’s why the unique open rate is the most robust metric for measuring email subject line performance and quality.
100 opens by the same person = 1 unique open
100 opens ≠ 100 different people opening your email
Stop measuring for total opens. Make the switch to unique opens and get ready to start optimizing your email subject lines to maximize the ROI-generating impact of all your future email marketing campaigns.
You may also like:
Letters from the Linguists is a collection of thought-provoking articles about language and new technologies, contributed by Phrasee’s team of AI language technicians. This post looks at the evolution of profanities from the Middle Ages to the present day.
10 Oct 2019
Our carefully curated selection of the best, funniest, and most interesting tweets from the world of marketing in September 2019.
03 Oct 2019
In light of HSBC Private Banking's research into the challenges female entrepreneurs face in business, Phrasee Co-founder and COO Victoria Peppiatt shares her perspectives and advice on how women may feel better supported and confident throughout their business journeys.
01 Oct 2019
Letters from the Linguists is a collection of thought-provoking articles about language and new technologies, contributed by Phrasee’s team of AI language technicians. This is the first post in the series, and discusses the relationship between idioms and innovation.
26 Sep 2019
There's no secret winning formula for email marketing success - but applying scientific rigor to language is one important way to boost your campaign success. Phrasee co-founder and Chief Scientist Dr Neil Yager shares his wisdom on language experiments that can make a big difference to your results.
12 Sep 2019
The best, funniest, and most interesting tweets from the best and brightest in the Twitter marketing realm from the month of August 2019. Let's see what Twitter's marketing pholks had to say this month!
04 Sep 2019
From start-up to scale-up, Phrasee has enjoyed remarkable growth since it was founded in 2015. This is our story so far in numbers, a story about an awesome team with bold ambitions, creativity, and innovation.
22 Aug 2019
AI is undoubtedly changing the world of work. But what exactly is the creative potential of AI? Can algorithms challenge us and push us creatively? In this post, we take a look at how AI is making inroads into creative fields such as art, film, journalism, copywriting and design.
07 Aug 2019
Our painstakingly curated collection of the best, funniest, and most intriguing tweets from the best and brightest in the world from the month of July 2019. Here's what the marketing Twitter community was tweeting about in July...
31 Jul 2019
Sender name and email subject line are the two elements of every marketing email that drive subscriber engagement in the inbox. But which of these crucial email elements has the biggest impact on email open rates?
24 Jul 2019
The push notification is one of 2019's most exciting, fastest-growing marketing channels. Messagegears' Product Owner of Data and Cloud Infrastructure Nick Zeich-Lopez offers his expert insights and tips on how to make push notification marketing work for you.
17 Jul 2019
In an increasingly crowded email marketing landscape, how your emails display in a subscriber's inbox matters. Email on Acid CEO and Co-founder John Thies dishes the dirt on email's "from fields" and how brands can get more out of their inbox display.
08 Jul 2019