Open, click, conversion rates and revenue per email metrics can either be calculated based on the number of messages sent or the number delivered. Each one is perfectly acceptable, providing you consistently stick with one method. However it could be argued that basing your metrics around the number sent is more appropriate for acquisition than retention.

For example, we use delivered messages as the base for the Naked Email metric. In retention campaigns delivery is an issue best measured and acted upon separately. In contrast, we would measure the effectiveness of acquisition campaign by the number of emails sent. This is essential when you are using rented email data. You paid for the number of email addresses that were sent, rather than those that were delivered so your ROI calculations should reflect that.

Check the following to best understand your metrics:

• Does your email service provider measure your campaigns against sent items?

• Or delivered emails?

Pay attention to maintaining the integrity of your data. If you change your settings or change provider ensure that all historical data calculations are also changed.

Open Rate

The number of opened messages (total or unique) divided by the number of delivered messagesآ (expressed as a %)

Use a combination of metrics, not just open rates as they are the least accurate of all the engagement metrics. Only HTML messages can be measured as “opened” and it is not possible to distinguish between an email opened and viewed by a person or the preview pane. By contrast a person with image blocking enabled might open and read the entire email’s contents but this will not be reported as an open.

However it is our view that the error will be fairly consistent, so over time with the same subscriber base, they should allow you to measure the impact of changes to:

• Subject lines

• Time, day or date of delivery

• From address

• Personalisation

Also, remember that there is a difference between:

Total open rate – the total number of times your email has been opened

Unique open rates – calculating each subscriber as one open no matter how many times they open the email

Some ESP’s report both however unique open rates are most commonly used.

The difference between these two metrics can provide interesting information. E.g. A big difference between the total open rate and the unique open rate may be an indication that your emails have long term value with subscribers continually referring back to it, or are regularly using it as a bookmark to get to your website.

You can also measure and track open rates over a period of time to map the lifecycle of your emails. Eventually your open rates will reach a peak after which time there are very few if any further opens. (See graph below) If this occurs quickly this would indicate that your email content is of immediate interest and or time-sensitive. Open rates that take a long time to peak are a sign of the situation described above, one where subscribers are referring back to your email content.

Opens over timeIt is not possible to determine if a text message has been opened, however you can infer that anyone who clicks on a text version or an HTML version received by people with image blocking enabled has opened the email. Some platforms do this automatically but with others you will need to do this manually.

There is a movement, led by the EEC to redefine the Open Rate as the HTML Render Rate, as it is a more accurate description of what occurs. Whilst ‘Render Rate’ is a more accurate description of this metric we will continue to use the term open rate as it is widely used and most understood metric name.

Click Rate

The number of total clicks (total or unique) divided by the number of delivered messagesآ (expressed as a %)

Click rates track your subscribers’ engagement with the received email message; they are a strong indication of the relevance and value of your email content. In general, the more links there are the more clicks will be generated. Even if the email campaign is purely informative it is worth trying to generate a click by using teaser text and a ‘find out more’ link to a landing page containing the rest of the message because you can build up a valuable database of each subscriber’s interests for future segmentation and targeting.

Click rates can also be calculated as total or unique, with the difference between the two again providing additional information on how much value subscribers place on your content:

Conversion Rate

The number of purchasers/transactions divided by the number unique messagesآ (clicked or delivered)آ (expressed as a %)

The conversion rate is the most important measure of engagement, your aim should be to adjust and optimise your strategy to maximise the number of people who transact with you in any of the following ways:

• Make a purchase

• Download a white paper

• Enter a competition

• Generate an appointment

It is advisable to integrate other information too; such as your website stats or sales data. This will ensure you have the most reliable figures available. Inevitably, some aspects will not be easily or reliably tracked like visits to a store. However, coupons or campaign specific phone numbers can be used to measure this metric accurately in an offline environment.

Your conversion rate is not purely determined by the content of your email; so in your efforts to maximise conversions you will also have to review other factors such as the design and copy and your purchase process.

It is important to look at the relationship between your click rate and conversion rate as it will highlight the areas that may need work, like your subject lines, email content, landing page content and purchasing process.

Revenue per Email

The total revenue divided by the number of emails deliveredThis metric gives you the average amount earned for each delivered email. This is useful to know when investigating the feasibility of investment into email marketing. The value an email address has to your company should guide your investments in data collection and maintenance as well as deliverability.

Other useful ways of looking at the value of your email activities include:

• Revenue per open

• Revenue per click

• Average order return

Last updated: Nov 05, 2014  admin

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