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Online Marketing Performance Indicators, Part 2: Open Rate
18.05.18 | 0 Comments | Author: Eva Pach

This blog entry in our series “Online Marketing Performance Indicators” is about the open rate of e-mail shots and newsletters. To evaluate the success of our newsletters and direct e-mail campaigns, we at CHEMIE.DE always consider the net open rate. Only e-mails that actually reach the recipients will ever have the chance to be opened. (The proportion of undelivered e-mails is the subject of part 1 “Bounces and Delivery Rate” of this article series.) And only these e-mails give us the opportunity to achieve greater success through optimisation.

open rate

Opened e-mails are detected through so-called web beacons (also known as tracking bugs): these are images that are embedded in the e-mails but invisible to the e-mail recipients. When the recipient opens the e-mail, the web beacon is loaded, which leads to it being registered and counted. This method of counting is also the disadvantage of web beacons because there are a number of reasons why such e-mails can be opened without being counted or, the other way around, unopened but counted.

For professional direct e-mail campaigns, it is usually recommended to create the e-mails in the so-called multipart format: in addition to an HTML version of the e-mail, a plain text version is also sent. If displaying HTML mails is disabled in the recipient’s e-mail client, a plain text version is shown. However, the web beacon method does not count opened plain text e-mails.

Likewise, many e-mail clients are pre-set not to automatically display images within e-mails, which includes web beacons. If this is the case, opened e-mails are not counted, unless the recipient subsequently activates the loading of remote images.

While the above two factors cause the open rate that you determine to be lower than the actual rate, the e-mail client’s preview window can lead to the opposite effect. If previewing is enabled, incoming e-mails are automatically displayed in the preview window, including any images contained. However, this does not constitute a willingness to open an e-mail and should therefore not be counted.

The bottom line is: the open rate can never be interpreted as the true value, even if the figure you find in your performance evaluation report is given in the precision of a hundredth of a percentage point! At best, such figures give you an approximate order of magnitude that can help you compare the open rates of one e-mail blast and another. However, because the shortcomings of the open rate apply to all e-mails from all senders, you should nevertheless be able to see what works better and what fares worse.

The e-mail marketing provider Inxmail, which we at CHEMIE.DE have used for quite some time now for our direct mail campaigns, looked at average open rates in e-mail campaigns as part of its German study “E-mail Marketing Benchmark 2015” (see graph below). According to this study, the 2014 open rates of B2B e-mail shots using customers’ own distribution lists averaged 27.7 %.

The average open rate for email campaigns, Source: “E-Mail-Marketing-Benchmark 2015, Inxmail”


The most important factor with which you can influence the open rate is the subject line of your e-mail. Apart from the sender, the subject line is the only other bit of information that recipients see before deciding on whether to open an e-mail. This is the moment when it is either deleted or opened for reading. The next blog entry of our series “Online Marketing Performance Indicators“, the part “Clicks and Click-Through Rate”, will take a look at what happens after the e-mail is opened and read.

At CHEMIE.DE we have gained valuable experience with testing different subject lines in A/B tests. This has given us insights into how the wording can affect open rates.

What is your view on the average open rates determined by Inxmail? Are there certain characteristics that set a successful subject line apart? Have you gained experience at A/B testing of different subject lines in your direct e-mail campaigns?

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