Contact Frequency and the Inbox

Contact Frequency and The Inbox

By John Landsman, Director, Strategy & Analytics

Every consumer survey on email attitudes tells us that a brand’s email subscribers object most to irrelevant messaging and over-mailing.  The two are inextricably entwined, because we also know that consumers do tolerate more frequent contact from brands whose email is relevant; i.e., targeted and personalized, based on known consumer preferences, location, status and behavior.  

But contact frequency is our primary focus today; specifically, how over-mailing can affect deliverability. The logic we’re demonstrating is that a brand’s over-mailing leads to lack of consumer engagement, which in turn makes it more likely that the ISPs (especially Gmail) will designate as spam a brand’s messages to its disengaged consumers.

Case-in-point:  The table below shows pertinent email metrics for four major national retailers in a particular category niche.  You’d recognize all their names.  The “Offender” is notorious for sending emails to a given customer multiple times per day!   During Holiday, their subscriber contact frequency reaches 4-5 times per day.  This despite the fact that many customers receiving this contact intensity have never opened or clicked on an email, or purchased from the brand.   The results speak for themselves.  Within this group, the “Offender” has the lowest Inbox Rate, and the worst Read Rate.

Contact Frequency

The “Offender” brand also has the lowest Delivery Index.  This metric is eDataSource’s unique real-time deliverability measurement, a single metric showing how a sending domain is performing at the four major ISPs: Gmail, Outlook, Yahoo and AOL.  Unlike other scoring systems, the Delivery Index measures a sending domain’s reputation across all of a brand’s IPs and ESPs.  The metric looks at your current sending behavior, your past sending behavior and the volatility of your inbox placement over time. Score Meaning:


  • 9-10:   Excellent reputation
  • 8-8.9:  Average reputation
  • < 8:     Poor reputation


Has the Offender’s excessive contact frequency caused their weak inbox and read rate performance?  We think that’s highly likely. We’re not saying that there’s an airtight statistical case that consistently binds these factors together; only that these relationships really matter, to your customers and to the ISPs. The relationships should be known to every email marketer — and to every senior executive driving risky audience acquisition and contact strategies.  We understand that there are trade-offs supporting the necessity for less optimized strategies.  But if that’s the case, you at least need to understand the costs of those approaches.  

There are two major implications here.  One is that you shouldn’t be mailing into audiences with no email engagement in more than 90-120 days.  The other takeaway is that optimizing email contact frequency requires a testing protocol, measuring the impact of various contact cadences on each of several consumer engagement-level segments.  The correct result permits relatively frequent contact to the most engaged subscribers, versus much less among less engaged subscribers.  

As always, knowledge is power!