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Study: Marketers Must Repair Poor Reputations To Reach The Inbox

Complaints, unknown users and spam traps kill reputation, block up to 36% of email

New York, NY – June 15, 2011 Return Path, the world’s leading email certification and reputation monitoring company, today announced the findings from its latest research report, “The Sender Reputation Report: Key Factors that Impact Email Deliverability.”  Available for download on our website, the report examines how email reputation significantly impacts a marketer’s ability to reach their intended  audience.  The results of the report urge email marketers to examine the critical factors impacting email marketing performance in order to ensure their emails are getting into the inbox.

“If you have a million addresses and 20% of your emails are blocked, you are missing 200,000 messages every time you hit ‘send,'” said George Bilbrey, President of Return Path.  “This means lost revenue, poor customer experience, increased customer service costs, lost branding opportunities and the inability to advance your message to your marketplace.  By understanding the impact email reputation has on email programs, marketers can take immediate and corrective action to ensure higher inbox placement rates.””

Understanding Email Reputation

There are three critical factors that ISPs and other large-volume mail receivers use to determine whether or not to block emails:

  • Reputation of a given email server, measured by complaints, spam trap hits, unknown user rates and similar metrics
  • Infrastructure set up which indicates a sender is a “real” mail server and not a botnet or spammer
  • Content associated with complaints, spam trap hits and unknown user rates

Return Path’s Analytics team reviewed data on complaint rates, spam trap hits and unknown user rates by Sender Score.  Sender Score is Return Path’s proprietary reputation rank, which is calculated by aggregating reputation performance data from a variety of ISPs, spam filtering and security companies.  For this reputation study, Return Path examined IPs by Sender Score bands on more than 18 million IP addresses, collected from 30 of the world’s top ISPs and other large-volume mail receivers representing over 2.1 billion mailboxes in North America, South America, Europe and Asia.  The study shows how reputation factors influence an IP’s Sender Score and how that correlates to Inbox Placement Rates (IPR).

Marketers Should Be Aware of Misleading Metrics

Many Email Service Providers (ESPs) proudly extol their high “accepted” rates to prove they deliver high IPR for their customers.  But only measuring “”delivered”” and “”accepted”” shows what is accepted for delivery at the ISP gateway, not what ultimately lands in the inbox.  Marketers must know exactly where their emails go, which requires an examination of more sophisticated inbox placement metrics.

Low Sender Score, Low Inbox Placement Rates

Return Path’s latest research shows that IPs with Sender Scores of between 41-50 have an IPR of 64% which means 36% of their email is blocked or diverted to a junk folder.  IPs with Sender Scores in the mid-range between 51-70 already show considerably higher average IPRs with 71% (Sender Score 51-60) and 76% (Sender Score 61-70) respectively. Notably there is a decline in email that is rejected right at the gateway, however, the study shows IPs within this Sender Score band have a high number of emails that are rejected at a point beyond the gateway.  Only IPs with the highest Sender Scores have email that is routinely “accepted” into an ISP’s system.  The average IPR for IPs with Sender Scores of 91 or greater is about 88%, which is significantly lower than the 99% “accepted” rate that many ESPs tout.

Reputation Factors: Complaint Rate, Spam Trap Hit Rate and Unknown User Rate

Three metrics that reduce email marketers’ IPR are complaint rate, spam trap hit rate and unknown user rate. Complaints lead to lower reputation.  Return Path’s study shows that complaints are relatively low, at 0.4%, for Sender Scores between 50 and 80 because the delivery rate is much lower.  People can’t complain about email they don’t receive.  Complaints hurt marketers when their email is getting delivered.  A high complaint rate with a high delivered rate is an indication that the delivered rate will soon start dropping if fixes aren’t implemented immediately.

Spam trap rate shows that the best mailers those with Sender Scores above 80 have few, if any, spam traps on their list.

Senders with better reputation metrics have cleaner lists.  When it comes to legitimate email, unknown user rates higher than 1% are problematic and should be addressed quickly.

Authentication and Reputation

Servers with good reputations are far more likely to pass checks for DKIM (DomainKeys Identified Mail) than those with poor reputations.  Return Path’s research finds that IPs with a Sender Score range of 90-100 are 42% more likely to pass DKIM versus IPs with Sender Scores of 70 to 79.  Even servers in the top range only pass DKIM at a rate slightly above 50%. Given the importance of authentication in protecting a company brand from spoofing and phishing, the proper implementation of authentication protocols needs to be top priority.

Study Methodology

Return Path’s Analytics team looked at the metrics for delivered, rejected and filtered rates by Sender Score bands.  The team also reviewed seedlist data from Return Path’s Mailbox Monitor tool from the entire 2010 year and from January- April of 2011 to determine IPR by Sender Score band.

About Return Path

Return Path makes email work better by scoring and certifying email senders from around the world. We help marketers, publishers and other large-volume email senders increase their response rates by providing the world’s leading inbox deliverability solution. We help mailbox providers and email administrators at ISPs and enterprises block unwelcome and malicious email by providing near real-time IP reputation scores and other data-driven tools. Taken as a whole, these tools and services improve the consumer experience of email by protecting them from spam, phishing and other abuse. Return Path offers free access to Sender Score, the email reputation measure compiled through our cooperative data network of ISPs and other email receivers, at our reputation portal Information about Return Path can be found at