Following the Data: Does Certification Really Help Deliverability?

Article by John Landsman

In our July 2018 Blogpost on Deliverability, we said:

“The email industry has spawned a number of services by which mailers can acquire what’s typically billed as an official stamp of approval, allowing messages anointed as trusted to pass through spam filters. Depending on vendor, these whitelist-type services carry names that are often variations on words like “certify/certification.”  Ours is called “Reputable Sender Accreditation.” Qualifying for these designations requires meeting a rigorous set of standards regarding the program’s mailing infrastructure, policies and practices, and domain and IP performance.  These services can be useful, but email marketers need to buy them with a clear understanding of what they will and won’t do.”

Return Path offers perhaps the best known (and most expensive) of these certification services.  Does theirs work?  Our 2015 analysis showed no useful difference in inbox performance between major retail brands that were, and weren’t, Return Path certified.  Recently, we set up to update that analysis.

The methodology¹ for our updated exercise identified the top 60 retail companies, as ranked by Internet Retailer; classified the group between those that do and don’t use Return Path Certification; and then tracked inbox and read rate performance, by ISP, for each company’s promotional1 email during Q2 of 2018.

The first notable finding was that only 25 (42%) of the 60 retail brands we analyzed are using Return Path certification at all.  This penetration is actually less than the over 50% so classified in our 2015 analysis.

As for actual certification impacts, the story is quite interesting.

The table below shows deliverability performance for the brands that are, and aren’t, Return Path certified.  There are no discernible inbox differences for any of the ISPs, except Outlook, where the certification advantage appears pronounced, although Outlook reflects only a small portion of the total activity we analyzed.

Yahoo Outlook Google AOL Global ISPs
Deliverability Percentage RP Certified 94.70% 85.50% 93.20% 97.60% 96.00%
Non-RP Certified 95.80% 60.40% 93.20% 97.70% 96.80%
% of Total Volume 19% 8% 69% 3% 1%

But Outlook.com does, uniquely, act on RP-certification that they see.  Therefore, they’re much more likely to have delivered RP-certified mail than the other ISPs, whose spam-filter algorithms have used other tests. For other mail, Outlook.com has definitely tightened up on inboxing rules based on the subscriber’s interaction and engagement with a brand’s messaging.

The table below shows read-rate performance for the brands that are, and aren’t, Return Path certified.  For every ISP, the non-certified activity outperforms the certified activity.  In fact, Outlook reflects the strongest positive differential.

Yahoo Outlook Google AOL Global ISPs
Read Rate RP Certified 12.20% 10.90% 11.40% 29.50% 20.20%
Non-RP Certified 23.50% 14.20% 11.80% 30.10% 20.60%
% of Total Volume 19% 8% 69% 3% 1%

Why this read rate advantage?  We hypothesize that many mailers with Return Path certification may see it as a safety net, become complacent in their list management, send frequency and other best practices. These mailers likely therefore pay the price of degraded engagement and conversion.    The lesson is that maintaining good list management, and best sending and authentication practices ultimately yields the best engagement performance.

And we know that subscriber engagement is the critical factor in most spam filtering protocols, especially Gmail’s.   Mailing to audience segments inactive for more than 60-90 days creates inbox problems, regardless of any official designation of a mailer’s strong “reputation.”

And we also know the key engagement drivers:

  • Mailing based on customer status across the full customer lifecycle.
  • Targeted/segmented messaging based on behavior, location and preference.
  • Management of subscriber contact frequency based on engagement levels. To retain certain audiences, less is sometimes more.

The bottom-line?  Buying an officially designated reputation as a “good” mailer may bring peace of mind, but that’s not what really gets you to the inbox.   As we’ve frequently said, what gets you to the inbox are the same best practices that got you the “good” reputation.  The certification is merely a roadmap to the practices which, if executed faithfully, are what really drive engagement and inbox performance, with or without “certification.”


¹Excluding transactional, loyalty, administrative and other corporate email.