Savvy email marketers who want to avoid deliverability issues already know to monitor their deliverability metrics obsessively. While traditional metrics such as open rates and clicks rates contribute significantly to sender reputation and engagement, most marketers already track those are part of overall campaign performance and business goals. Deliverability focused metrics such as bounce rates, spam complaints, and spam trap hits are just as important for tracking overall success of the email program, but often forgotten until after a deliverability issue arises. Keeping regular tabs on all of these metrics is what makes the difference between maintaining a strong sender reputation and potential blocking or bulking issues. Here are a few recommended ones to get started with:
1. Breaking down bounce rates
A "bounce" is when an email is sent and then immediately returned with a notice that it was not delivered. There are two types of bounces that marketers should pay attention to: hard bounces and soft bounces. The main differentiator between the two is that hard bounces are permanent and emailing to them should not be attempted again, whereas soft bounces are temporary and can be re-tried. It is very important to note that should you retry sending emails to hard bounces, you run the risk of affecting your reputation as a sender, and also damaging overall deliverability.
2. How to avoid spam complaints
Omnipresent spam complaints are based on abuse reports received from the ISPs currently offering feedback loops. For email marketers, spam complaints are indeed a major factor in determining inbox placement. When recipients hit the spam button, even in small numbers, a sender’s reputation dips, resulting in messages being filtered to the bulk folder, which sometimes results in delayed or blocked delivery.
To counter this, measure spam complaint rates on a daily basis and also look at 7-day and 30-day rolling windows. Keep in mind that not all ISPs report back their users’ spam complaints. Gmail, for instance, does not provide spam complaint data on individual recipients. Windows Live Hotmail/Outlook.com, Yahoo, AOL and others do provide this via feedback loops.
3. Spam traps 101
Under the guise of “one size does not fit all” it is important to review spam complaint rates at each individual ISP in order to gain an understanding of how user behavior and deliverability varies across email providers. Moving beyond spam complaints, one of the most damaging issues for email deliverability and maintaining proper list hygiene are spam traps.
There are two types of spam traps.
Avoiding these spam traps requires diligent monitoring of engagement levels and removing inactive subscribers. While any type of spam trap hits are damaging to a sender’s reputation, pristine trap hits are exponentially worse.
4. Microsoft SNDS and Return Path Sender Score
Another email metric marketers should use is Microsoft Smart Network Device Services (SNDS). Specific for email sent to Microsoft’s Hotmail/Outlook.com network of subscribers only, SNDS provides data about the traffic seen originating from unique IPs, such as email volume, complaint rates, and spam trap hits.
One final metric to focus on is Return Path Sender Score, which serves as a helpful benchmark for reflecting how ISPs may view the reputation of your sending IP address via Reputation Monitor. Given the fact that 83% of email delivery failures are caused by reputation problems, it is extremely important to monitor your score, which brings together various metrics, sending patterns and trends displayed by the sender and plugs them into a proprietary formula to come up with a score ranging from 0 to 100. Reminiscent of our grade-school days, this can serve as a periodic report card or health-check for your email program’s reputation.