Email IPR Correlates with Sender Score

June 15, 2011

returnpath-average-score-june-2011.JPGThe average inbox placement rate (ISP) for promotional emails correlates with the sender score of the entity sending them, according to [landing page] a study conducted from January to April 2011 by ReturnPath. Data from “The Sender Reputation Report” indicates that emails from IP addresses with the highest sender score (91-100) have an average 88% ISP rate.

Top Sender Score Equals 38% Higher Email Success

In contrast, emails from IPs with the lowest sender score that still indicates a legitimate address (41-50) only have a 64% ISP rate. That means IPs with a sender score of 91-100 are 38% more likely to get an email into an inbox than IPs with a sender score of 41-50. ISP rate steadily climbs along with sender score; industry average ISP rate is 80.

Complaint Rates Fall as Sender Scores Rise

returnpath-complaint-rate-june-2011.JPGConversely to ISP trends, the rate of email complaints falls dramatically as sender score rises. IPs with a sender score of 41-50 receive complaints on 1.7% of the emails they send. This rate falls 76% to 0.4% for IPs with the next-lowest sender score (51-60), and then stays flat until dropping another 75% to 0.1% for IPs with a sender score of 81-90. IPs with the highest sender score essentially do not receive email complaints.

Unknown User Rates Fall Dramatically with Sender Score above 70

returnpath-unknown-user-june-2011.JPGUnknown user rates show an interesting pattern where IPs with a sender score of 41-50 have the second-lowest rate (7.3%), while IPs with the slightly better sender score of 51-60 have the highest rate (9.1%). ReturnPath credits this to the relatively low number of emails that IPs with the lowest sender score get into recipient inboxes.

Unknown user rate for IPs with a sender score of 61-70 is 5.5%; this tumbles 71% to 1.6% for IPs with a sender score of 71-80. IPs with a sender score of 81 or higher have unknown user rates of less than 1%. ReturnPath advises an unknown user rate of more than 1% is problematic and needs to be addressed.

Spam Trap Rates Somewhat Erratic

returnpath-spam-trap-june-2011.JPGThe spam trap rate shows a slightly erratic pattern, with IPs having a sender score of 71-80 reporting the highest spam trap rate of 1.3%. However, ReturnPath analysis indicates this is mainly because the numbers are so small that relatively small variations look like big differences. The main point is that the best mailers, those with sender scores above 80, have few, if any, spam traps on their list.

DKIM Rates Low across the Board

returnpath-dkim-june-2011.JPGServers with good reputations are far more likely to pass DKIM (DomainKeys Identified Mail) than those with poor reputations. In fact, ReturnPath research finds that IPs with a sender score range of 91-100 are 42% more likely to pass DKIM compared to IPs with Sender Scores of 70 to 79. But the fact remains that even servers in that top range only pass DKIM at a rate slightly above 50%.

Given the importance of authentication in protecting a brand from spoofing and phishing, ReturnPath recommends that the proper implementation of authentication protocols needs to be top priority.

ExactTarget: 9 in 10 Email Users Have Unsubscribed

Nine in 10 (91%) US email users have subscribed to a company’s email and later decided they don’t want to receive it, according to a February 2011 report from Exact Target and CoTweet. Data from “The Social Break-up” also indicates 18% of email users say they never open email from companies, and 77% of all US online consumers say they have become more cautious in the past year about giving their email addresses to companies.

About the Data: Return Path reviewed data on more than 18 million IP addresses, collected from 30 of the world’s top ISPs and other large-volume mail receivers. These ISPs represent mailboxes in North America, South America, Europe and Asia. The team reviewed data on complaint rates, spam trap hits and unknown user rates by Sender Score bands. The data shown is for Sender Scores of 40 and above. Sender Scores from 0-39 were not included in this study, as these servers are unlikely to be sending legitimate email. The team further looked at the metrics for delivered, rejected and filtered rates by those same bands. Finally, the team reviewed seedlist data from our Mailbox Monitor product from 2010 and January through April of 2011 to determine IPR by sender score band.

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