Why Email Open Rates Are Still Relevant for Marketers

Email open rates have long been regarded as a key performance indicator (KPI) for email marketing campaigns. The value of knowing there’s an active subscriber behind an address, and that they are interested in your product or service, opens up the possibility of driving future sales. However, over the last several years, the narrative has shifted around the email opens – they aren’t being considered a reliable metric of engagement. 

Here’s why: changes to inbound filtering at many mailbox providers have led to an increase in non-human interactions (i.e. bot opens and clicks) occurring as mail arrives on their servers. As mailbox providers focus has shifted to providing the safest inbox experience possible for their users, a change has occurred for marketers in terms of how engagement can accurately be measured.

Opens may no longer serve as an absolute measure of engagement, but when looked at alongside click-thru and conversion data, they can still help to paint the larger picture of how your campaigns are performing and indicate how your reputation as a sender is viewed by mailbox providers. Let’s take a deeper look at how email open rates are still relevant.

Email open rates are still a good performance indicator

While mailbox provider solutions like Apple’s MPP have changed the game, email open rates can still be used to determine how your campaigns are performing when the data is looked at in aggregate over time. A decrease in opens can suggest potential bulking/blocking issues, subscriber fatigue, or a need to review your content for relevance and a clear call to action. A spike in opens might suggest an influx of new signups to your brand, that a campaign or content resonated well with your audience, or that there were bulking/blocking issues that have recently been resolved.

Are open rates declining across the industry?

This question came from a customer who had seen a blog from a third-party service provider that suggested open rates are declining across the board. The article concluded that Apple had adjusted their inbound filtering in April of 2024, which led to a decrease in the number of open pixels being pre-loaded across their service, directly resulting in an overall drop in open rates.

We wanted to take a look at our data to see if we could locate a larger issue around declining opens. Looking back at the last two years (2023 and 2024), the data shows open rates have actually risen from an average of 33.07% in 2023 to 36.24% in 2024. Something that’s consistent across both of these years is a decline in open rates beginning around March that starts to correct around late August.

This decline in open rates was slightly more pronounced in 2024 than it was in 2023, so it’s worth thinking through what might have led to that beyond the standard lack of holiday sales for marketers to promote. Sender Guidelines enforcement (Yahoo and Gmail) may have been behind some of it as a small amount of mail was likely being blocked or delivered to the spam folder due to lack of proper authentication. 

AI-generated summaries at Gmail (and a number of other inbox providers) could be a factor that led to fewer opens since subscribers could get the key points from the inbox. Finally, the inbound filtering changes at Apple mentioned in the third-party piece could be playing a factor, though it’s important to call out that there also seems to be a seasonal trend of drops in open rates that correlates with the timing.

It isn’t uncommon for mailbox providers to make periodic adjustments to their algorithms for inbound filtering. Because of the adjustments mailbox providers make periodically, it warrants looking at trends over time rather than sudden drops/spikes in open rates.

Dimiter Batmazian, senior manager of solution consulting at Salesforce, shares another important consideration around list hygiene and content personalization that can affect subscriber engagement metrics: “There is an aspect of over-saturation with big senders that ’set it and forget it’ with their content and campaigns,” he says.” I expect fluctuation and think open rates will naturally wean over time until you revitalize your program or change the segmentation.”

Tips for what to do if your open rates are declining

Go back to the beginning and confirm you’re meeting compliance standards with Sender Guidelines. Assuming everything checks out there with your sending domain(s), your next step would be to look at your trends over time to see if you can pinpoint a specific job/campaign that may have caused bulking or blocking issues. 

Your tracking data can usually clue you in here if a drop in opens or clicks occurred and correlates with a spike in volume, use of an older customer segment, or new content. Isolate the issue, work to resolve it ,and engage your ESP’s support team if assistance is needed. If there’s nothing standing out at this point, it’s probably time for some introspection on the audience age/engagement rates and relevancy of the content being sent. It’s okay to let lapsed subscribers go, as having a proactive lifecycle plan for unengaged subscribers improves your open rates, and sender reputation and drives up your ROI.

Open rates were at some of the highest levels we’ve seen in the last two years in November and December of 2024. While the value of the open as a metric of engagement is gone, it’s still an important factor in determining overall trends to spot issues like bulking/blocking or noticing the seasonal trends that occur in the summer months when more subscribers are away from their inboxes on vacations, and a lack of holidays leave many companies without sales to promote. 

Much like email, the open isn’t quite dead, and knowing how to use it properly can provide you insights to help you succeed.