Ever Heard of the Active Unique Open Rate?

When it comes to email marketing, you’ve probably heard of a unique open rate or total open rate. But another interesting metric to track is your active unique open rate—the number of opens by the active members of your list. It gives you a better picture of the extent – month to month – that you’re meeting your subscribers’ interests.

To understand all of these metrics, let’s quickly review the standard ones we’ve been using:

• Unique open rate – the unique number of individuals who opened an email at least once. If you have 1,000 subscribers and 200 opened the email at least once, you have a 20% unique open rate.
• Total open rate – the total number of times an email was opened. Sometimes subscribers open an email more than once, so all of those opens count in this metric. If you have 1,000 subscribers and 200 people open the email a total of 550 times, for example, your total open rate is 550/1,000, or 55%.

When looking at what we’re calling the “active unique open rate,” you first need to know how many users are active. I’ve written plenty on inactive versus active users; you can learn more here: Active versus Inactive Users: Who’s on Your Email List?

The active unique open rate looks not only at the unique open rate, but also at the actual active users on your list. You can define active by choosing the appropriate parameters for your list. For a monthly newsletter, you may consider calculating the number of people who have opened at least one newsletter over the last 6 months. If you have 1,000 subscribers and 200 people open the newsletter, for example, but only 400 have opened an email over the last 6 months, the “active unique open rate” is 200/400, or 50%.

The question becomes whether this metric has value. We argue that it does. In email marketing, we are constantly analyzing whether the emails continue to be relevant to our audience. (Remember that Seth Godin preaches relevance as one of the three most important foundational elements of successful permission marketing.) This metric helps uncover relevance, albeit a bit more dramatically than our standard measurements.

By reviewing the “active unique open rate” over several months, you’ll get a much more dramatic picture of whether your content is resonating. If you have a large list with many inactives (e.g., 70%), a slow drop-off in readership may not be all that obvious. Looking at the “active” metric in conjunction with your total active users, however, presents a clear picture of whether your content is resonating. If you see your “active unique open rate” declining while your total active users are also declining at a high rate, you have a problem.

Also, if you’re disappointed with an email open rate of 7%, have a quick look at the “active unique open rate.” That presents an entirely different picture. You may discover that your 10-year-old list has a lot of inactive users and your active unique open rate is actually 40%. If your list is not experiencing a significant annual attrition rate (i.e., you’re losing “active” subscribers at an alarming rate, such as more than 25%), then you may actually have an open rate to be proud of.

Let us know what you think of this metric. We’re interested in what it tells you for your list.