• by Ray Schultz , Columnist, May 8, 2018

Microsoft inboxes are the hardest to get into for even the best email marketers: the average placement rate was 72% last year for firms with a Sender Score above 90, according to the 2018 Sender Score Benchmark, a study from Return Path. In general, senders with that high score saw 91% of their email hit.

What is a Sender Score? It’s an evaluation of a firm’s sending practices, as defined by Return Path.

For firms hitting the 90 mark, AOL inboxes are the easiest inboxes to penetrate, with a 97% placement rate. Yahoo is second with 91% and Gmail is third, with 81%. Microsoft is getting tougher — its delivery rate is down from 79% in 2016. 

In general, there is a “strong correlation” between the qualities you need to get a good Sender Score and good inbox placement.  

For example, firms with a score of 60 or lower will see less than half their email get delivered to Microsoft, AOL and Gmail inboxes, with Yahoo Mail the most forbearing. There is little margin for error: Those with a Sender Score from 81 to 90 can expect a 68% placement rate, and firms with 71 to 80 can expect a 42% rate.  

Among industries, the highest inbox placement rate — 97% — is enjoyed by the distribution and manufacturing sector. That may reflect the rise of its sender score from 83 in 2016 to 90 last year.

The lowest deliverability rate — 76% — belongs to the education/non-profit/government sector. Meanwhile, the biggest sender score increase was achieved by the technology/software/internet category, which rose from 80 to 91.

Things are getting better overall, Return Path notes. In 2012, when it started this benchmark, the firm found that 60% of all messages came from disreputable senders with a score of 10 or below. Firms with a score of 90 contributed only 6% of the volume.

And now? Mail from the least upstanding mailers has fallen to 25%, while mail from those in the 90 bracket is up to 36%.

This is largely because it is “increasingly difficult — and expensive — to successfully send spam,” Return Path notes.

So what does it take to get a good Sender Score? There are three metrics, according to Return Path:

• Complaints — These occur when an email is flagged as junk or spam. Firms with a 90 Sender Score had a complaint rate of less than 1%, and they were the only ones. Senders with a score of ten or less were hampered by a 7.4% complaint rate.
• Unknown users — These are email addresses that either never existed or were closed by the provider or abandoned by the user. Senders with high percentages of hard bounces will be seen as having poor list hygiene, and treated accordingly. Firms with Sender Scores of 90 or over have unknown user rates of 1%.   
• Spam Traps — These email addresses are used to identify spammers and senders with poor data. The top scorers hit an average of 0.35 spam traps, compared with 7.5 for firms with a score of ten or less. 

“Year after year, our research shows a clear link between reputation and deliverability — so it’s absolutely critical to monitor your sender reputation and maintain it at the highest possible level,” concludes Tom Sather, senior director of research at Return Path.

Return Path analyzed over 6 trillion messages in 2017 from IP addresses with a calculated Sender Score.