How Engagement Metrics Influence Deliverability

Many senders have noticed changes in the way that ISPs do their filtering, notably at the big four of AOL, Yahoo, Microsoft and Google, and have been scratching their heads as to what changed, and what can they do now to get delivered back to the inbox. The answer is in how ISPs are calculating sender's reputation scores (hint: it's really not that new). Less than savory senders are always looking for ways to game the system to bypass current filtering methods. As a result, ISPs and email providers are constantly changing and improving their filtering methods.

The major email providers are already using, or plan to use, a broad set of engagement metrics to determine inbox placement, not just clicks and opens as has been widely reported, to determine the level of user engagement for different senders. These include:

  • "This is not spam" (a.k.a. TiNS) data – Used by all email providers who also have a "this is spam" button. It's the tried and true test to see if a marketer's emails are relevant and desired, as well as a way to gauge if the email provider's spam filters are working or not. If your subscribers really want your email, they'll look for it in the spam folder and vote it back to the inbox by clicking the "This is Not Spam" button. This measure of engagement is still as important as ever.
  • Panel Data – A panel of users that the email providers employ to verify if spam folder placement is correct and warranted. These users are real subscribers, but have to take the extra step in analyzing the email they received and asking themselves if they think it's truly spam or not. Their decision is based on qualitative requirements that the email providers specify.
  • Trusted reporter data – As my colleague JD Falk alluded to in his previous posting, mailbox providers have weighted complaint and "This is Not Spam" rates based on subscriber level data to determine if they're real users and not mailboxes set up to game the system. They also take into account users that are overzealous in voting everything as spam or everything as "This is Not Spam." As a result, only trusted reporters are calculated into the engagement measures.
  • Inactive accounts – No, not unknown users or even users that haven't clicked through on emails for awhile, rather users that haven't logged into their email accounts for long periods of time. This indicates to mailbox providers that you could be trying to pad complaint rates by not removing inactive accounts, or that you have issues with list quality. By keeping these on your list, you're only lowering your "This is Not Spam" rate even more and further reducing your chances of moving out of the spam folder.

Again, it's important to know that all the major mailbox providers are using, and have been using, a much broader set of engagement metrics like the ones mentioned above which can more accurately predict subscriber engagement, relevancy, and deliverability. For example, transactional notifications in which users often just read the subject lines and then delete would have deliverability issues due to low opens if not for "This is Not Spam" votes and Panel Data.

So what should marketers being paying attention to, besides complaint rates, to keep their deliverability rates up? Sophisticated marketers will look at the data they currently have at the subscriber level to see when subscribers clicked, opened or converted in addition to data available through Return Path to identify their most active and engaged customers and subscribers.

Here are a few ideas:

  • Obtain the highest level of permission possible for your business model. Set expectations accordingly from the start on things like offer type and frequency, and send a welcome message that reminds subscribers of all these items and allows them to unsubscribe easily if they get cold feet.
  • Create a preference center. Offer your subscribers more of a choice in things like frequency of messages or types of messages received based on their interests. Encourage your subscribers to change their preferences over unsubscribing to keep them happy and engaged.
  • Look at your cadence, a measure of engagement, as opposed to frequency which is a measure of volume. Only send to these addresses when they are in the market and more likely to respond. If certain groups are only in business, or responsive, once a quarter, only send to them once a quarter. Mail your active users more frequently and as long as they are active and in the market.
  • Send a win-back campaign to your inactive subscribers at least every three months, if not more, and make sure you do optimization testing on all campaigns, like subject lines and call-to-actions, to drive higher response rates. It's especially important only to send relevant campaigns to this segment as relevancy and response are highly correlated. If your subscriber has only bought men's clothing, don't send them campaigns on sales of women's clothing.
  • Use segmentation techniques based on clickthrough behavior. While not used by mailbox providers, click rates are already available to most marketers, and can be used to increase subscriber engagement. By creating segments based on what people are clicking on, and then sending more similar content to these users, could help keep your subscribers engaged in the long run, and will likely generate more revenue from your existing list. It also prevents email delivery from worsening, as well as unnecessarily spending more money to increase list sizes.

Try to reach a higher level of sophistication with your data to achieve these results. Marketers, now more than ever, need to lose the "batch and blast" mentality for the sake of both response and deliverability. Return Path can also help solve marketer's delivery problems with the data that's available to us. Learn how we can help.


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