Back to Basics: Email Marketing Metrics

One of the most appealing aspects of email marketing is the ability to measure its success. As the mid-year approaches, let’s get back to basics and review some campaign metrics and their usefulness in measuring email marketing success. This is particularly important before attempting to integrate with other digital channels and trying to quantify the relative impact of email as a business driver.

Analyzing performance metrics can be a bit more challenging than it may initially seem. Because there is so much data available, it can be difficult to sift through and identify the metrics that give you the quickest feedback on your success. Add to that the lack of standardization around email metric definitions and you may be left scratching your head.

There are two categories of basic email metrics. The first consists of the classic engagement metrics. The second category looks more deeply into the conversion aspect of your email programs and typically involves monetary analysis. (Of course, there are many other components to consider when evaluating your email program’s success, but getting the basics right is a vital first step.)

Classic Engagement Metrics

Classic engagement metrics, or those that indicate campaign activity, are the metrics with which we are all most familiar. And with that familiarity comes a bit of convolution as we consider several varieties of these basic metrics. What is most accurate, relevant, and/or usable? We primarily consider measurements of opens and clicks in this category. And we often consider both total and unique counts and rates for each. These metrics are aimed at evaluating different aspects of your email efforts as follows:


Total Opens measures the number of times a given campaign is opened. This is typically achieved via a count of the number of times an invisible pixel is loaded.

Total Open Rate simply takes the total email opens divided by the net delivered emails for the campaign to express a percentage of total email opens.

Unique Opens is similar to Total Email Opens, but here, the measurement aims to count an individual opener only once regardless of the number of times that recipient may have opened the email in total. The goal with this metric is to better understand the number of unique individuals who viewed an email campaign.

Unique Open Rate takes the unique email opens divided by the net delivered emails for the campaign to express a percentage of unique email opens.

It’s important to note that these metrics are not perfect. By virtue of the nature of measuring an invisible pixel it is likely that some opens will not be detected. This is particularly true when recipients do have images on and occasionally when they’re viewing from their mobile device.


Total Clicks aims to measure each click on a link for the campaign. Many times your unsubscribe link (and any other links you choose) is excluded from this measure to help get a picture of engagement with the campaign (rather than the negative result associated with the unsubscribe link).

Total Click-Through Rate (CTR) takes the total clicks divided by the net delivered emails for the campaign to express a percentage of total click-throughs.

Unique Clicks measures how many unique individuals clicked on at least one link within the email.

Unique Click-Through Rate takes the unique clicks divided by the net delivered emails for the campaign to express a percentage of unique click-throughs.

Click-to-Open Rate is gaining in popularity, as it can be done specifically for mobile opens and clicks, allowing for a better gauge of mobile “action.” It measures activity of combined opens and clicks. In other words, the number of individuals who clicked after opening and can be done for both total and unique opens and clicks.

Conversion Metrics

Conversion metrics attempt to evaluate the effectiveness of a campaign’s call-to-action. Most often conversion metrics seek to tie revenue to a given campaign. I’ll highlight a couple here to illustrate:

Email Conversions attempts to look at the applicable metric of success and understand how well the campaign succeeded in converting recipients. Some examples include registrations, preferences, sweepstakes entries, and, of course, purchases.

Email Conversion Rate is the percentage derived by taking the email conversion divided by the net delivered.

Email Revenue calculates the revenue generated as a direct result of the campaign. Oftentimes marketers will take this to the next level and calculate the “revenue per net delivered” to get a better sense of how much revenue, on average, can be tied to a single email in the campaign. Of course, this metric only accounts for revenue directly attributed to the last click; it does not include purchases that may have been influenced by the email either in a subsequent online session, or offline.

With a clear understanding of the basics, you’ll be ready to evaluate your campaigns, look to more advanced analysis, and better correlate your results in relation to benchmarks and industry information. Stay tuned to explore these and other topics with me in future posts!

Image on home page via Shutterstock.

Editor’s Note: As 2013 comes to a close, we’re pleased to share our top email columns of the year. This article was originally published May 21, 2013.

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