Email Frequency and Secondary Clicks
Many email marketers measure their success by open rate. But what determines the open rate? Essentially it's the interest that recipients have in the content being delivered to them. It's always been assumed by some that there's a relationship between email frequency and open rate — by overmailing you turn people off and they fail to open your emails. But this, in fact, might not be true.
To get to the bottom of the situation, I analyzed 213 email marketers who collectively sent 2,075,466,666 emails per month to 414,947,422 subscribers (an average of five emails per month per household). The frequency varied from 0.018 emails per subscriber — a fraction of one email per month — to a high of 48 emails per household in a month. (See chart 1 in the photo box.)
There's a risk in using open rate as an indication of interest in an email campaign — if a subscriber uses a reading pane (as most email subscribers do), as they move down the inbox each reading pane sends back a message to the marketer that this particular email has been opened even if the subscriber may not have really looked at the email at all. Therefore, you have to take email open rates with a grain of salt. If the conventional wisdom is correct, those who mailed more than several times a week should have lower open rates than those who mailed only a few times a month.
But our research didn't bear that wisdom out. The open rates varied all over the lot, as shown in the second graph in the photo box.
The answer to the effect of frequency on open rates has to lie somewhere else. It must be the content of emails that determines the effectiveness of their message. Content is measured by relevance to the recipient. Some marketers have gone to great lengths to try to define relevance. e-Dialog, for example, has six factors that it uses to score relevance. They are:
- lifecycle management;
- contact management;
- personalization; and
- testing and measurement.
Email marketers can score their own emails to determine their relevance. Unfortunately, we don't have a relevance score for these 213 marketers studied, but we do have a number that can serve as a substitute for relevance: click rate. If a person not only opens their email but also clicks on something within the email, the email must be in some way relevant to the subscriber. If it weren't, time wouldn't be wasted clicking within the message.
The most important clicks to measure are secondary clicks. Open rate doesn't count for much — it could have been the reading pane. The first click is much more important — the subscriber is reading the email and clicked on it. This shows real interest. But additional clicks beyond a first click are the absolute best indicator of relevance. Any email that was clicked twice or more is clearly of interest to the recipient. (See the third graph in the photo box for the percentage of secondary clicks for the 213 email marketers studied.)
This graph reveals that there were very few secondary clicks — the median average is 0.92 percent. These were clicks from people for whom the emails were really meaningful. We can now compare these secondary clicks to the frequency of emails sent (see the fourth graph in the photo box).
You can learn a lot from this graph. Sending one or less emails per month proves to be quite relevant to subscribers. These are careful marketers who don't flood their subscribers with emails. This strategy tends to result in more secondary clicks. Once you get into two or more emails per month, interest is greatly reduced. The numbers support the conventional wisdom that frequent emails reduce the interest of subscribers.
But there are marketers who are sending 20 or more emails to their subscribers per month. Subscribers who haven't opted out when bombarded with this many emails are clearly interested in the content they receive.
Therefore, if you want to learn how well your emails are received, measure secondary clicks. Messages that get clicked twice or more are of interest to your subscribers, and should produce meaningful sales.