Top 5 Reasons Why Your Email Open Rates May Be Falling

By Kathryn Barrett

Published on 9 Nov, 2021

Open rates are sometimes called vanity metrics. With Apple’s recent privacy update, their validity is being called into question even more. However, open rates still indicate a major goal of email marketers, subscriber engagement. With engagement, comes trust. With trust, comes revenue. Here are some of the more common reasons why open rates decline for email campaigns.  

Email Deliverability Problems

Email Deliverability covers a wide range of subtopics, including authentication (SPF and/or DKIM setup) and spam traps (bad email addresses used to catch senders who don’t clean their lists or who purchase lists from 3rd parties). Be sure you have good deliverability. Without it, the other reasons on this list are moot points.

ESP-provided “deliverability rates” can be misleading. Often, they derive from a calculation of email addresses sent for a given campaign that simply didn’t bounce the email back. ISPs have several layers of protection before allowing an email into a given inbox. 

List Maintenance

First, let’s talk about list fatigue. Open rates decline over time if a company doesn’t replenish their list with new contacts. The Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes. This often occurs in email lists where the largest portion of engagement comes from the newest portion of the lists. We recommend companies regularly review email acquisition tactics to ensure they continue adding new contacts to their lists.

Next, look at the overall segmentation. Is a large portion of the list unengaged? Have subscribers opened or clicked in the past 12 months? If not, we recommend removing them from baseline campaigns, as disengaged subscribers have an adverse effect on the overall deliverability rate. In fact, nboxes look at subscriber engagement and view a large amount of inactivity as a red flag. 

We also recommend cleaning lists by removing any subscribers who haven’t received an email in more than 12 months. This not only helps your reputation, but it could also save you money in maintenance costs for your database. If you’re using SFMC, see how here.

Send Times (and/or Seasonality)

Despite being the most straightforward and easiest to control factor, send times can majorly impact engagement. Let’s say the decline in open rates came from a campaign regularly sent out each month. Are they always sent at the same time? How about the same day of the week? Did one of the sends go out during a major holiday? Does the company consider seasonal purchases or always keep products the same? These questions help clarify whether or not the time of send of a given campaign had an impact on the open rate.


Perhaps the company sends too much email. Perhaps they don’t send enough. Infuriatingly, no “right” amount of email to send each month exists. It truly depends on the business. It depends on the amount of content available. It depends on why subscribers gave their email addresses. It depends on the time of year. It depends on inventory. It depends on unsubscribe rates. It depends on historical engagement rates. It depends on the email team’s bandwidth. It depends on the subscriber engagement level. And so forth.

The ideal frequency always changes. We recommend taking inventory of how much available content exists for the email team to use. Start small. Test sending once a month vs. twice a month, twice a month vs. four times a month, etc., until a balance appears of conversions, opens, clicks, and unsubscribes.


Companies often find content difficult to address. Understandably, stakeholders sometimes take content criticism personally. Nonetheless, we must consider all elements that could lead to a decrease in overall engagement. While content may seem like an obvious reason, companies often overlook it.


In the travel, tourism, and hospitality industry, a discount will most likely resonate with the audience more than late checkout times. Both angles feature the hotel, but one leads to higher engagement and more bookings than the other. Testing different content helps pinpoint what content works best for the subscribers.

From names, from email addresses, subject lines, primary content, preheaders––all of these elements impact open rates. We recommend constantly testing different aspects within your emails using a methodical, iterative testing plan to understand what best resonates with the subscribers in each segment of your list.

Need help developing a test plan or have questions about our list? Reach out to the Shift Paradigm Experts Today.



Written By Kathryn Barrett

A skilled Program Manager with 10+ years’ experience and a passion for retail. Skilled at building collaborative cross functional working relationships with internal and external partners. A passion for driving adoption and implementation of process and programs across teams. Experienced at creating a culture of accountability and driving key company initiatives and project deliverables.
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