Top 5 Reasons Why Your Email Open Rates May Be Falling

Scott Burdsall

3 minute read

A solid email open rate is one of the first signs of success when sending an email marketing campaign. It shows that email subscribers are indeed engaging with a campaign that may have been weeks in the making. Consequently, a decline in open rates between campaigns or over time can be unnerving (to say the least). Let’s go over 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). It is important to ensure you have good deliverability; otherwise, addressing the other reasons on this list will be a moot point. 

“Deliverability Rates” provided by ESPs can be misleading. Often, this is a calculation of email addresses sent for a given campaign that simply didn’t bounce back. ISPs have several layers of protection before allowing an email into a given inbox.

If you are not sure how many of your emails are making it to the inbox, please reach out.

List Maintenance

First, let’s talk about list fatigue. Your open rates can decline over time if you aren’t replenishing your list with new contacts. The Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes. This is often the case with email lists where a large portion of your engagement is coming from the newest or most active portions of your list. Look at your email acquisition tactics to ensure new contacts are still being added to your lists.

Next, look at the overall segmentation of your list. Is a large portion of your list unengaged? Have your subscribers opened or clicked in the past 12 months? If not, you should probably remove them from your baseline campaigns, as this can have an adverse effect on overall deliverability rate–inboxes look to see how engaged your subscribers are, and a large amount of inactivity from your subscribers can be a red flag.

Cleaning your lists is also recommended if the list hasn’t been sent to in over 12 months. Third parties like Webbula can help with this process.

Send Times (and/or Seasonality)

In my opinion, this is the most straightforward (and the easiest to control). Send times can have a major impact on engagement. Let’s say the decline in open rates came from a campaign that is regularly sent out each month. Are they always sent at the same time? How about the same day of the week? Was a major holiday celebrated during a deployment time? Does your business have a seasonal purchase consideration? These questions can help clarify whether or not the time of send of a given campaign had an impact on the open rate.


Perhaps you are sending too much email. Perhaps you are sending too little. I’m often asked, “What is the right amount of email to send in a month?” The infuriating answer is “it depends.” It depends on the business. It depends on the amount of content available. It depends on why subscribers gave you their email address. 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 your email team’s bandwidth. It depends on the subscriber engagement level.

The ideal frequency can be a moving target, and one that can have an impact on your open rates. I recommend taking inventory of how much content is actually available for the email team to use, then starting small–test sending once a month vs. twice a month, twice a month vs. four times a month–until you see a balance between conversions, opens, clicks, and unsubscribes.


This is usually the one that is most sensitive to address. Sometimes stakeholders take content criticism personally, and I understand completely. However, we need to consider all elements within a campaign that could have led to a decrease in overall engagement, and a big part of that is the actual content deployed within a campaign. This may seem obvious, but it is often overlooked.

If you’re in the travel, tourism, and hospitality industry for instance, and perhaps want to promote a discount on hotels, it is likely that a discount will resonate with your audience more than late checkout times–an extreme example, but hopefully one that illustrates my point. Both angles are technically featuring your hotel, but discounts may lead to higher engagement and bookings.

From names, from email addresses, subject lines, primary content, preheaders–all of these elements can impact your open rates. You need to constantly test content within your emails using a methodical, iterative testing plan to understand what best resonates with each segment of your list.

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

Trendline Interactive

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About the Author(s)

Scott Burdsall

Scott Burdsall is the Practice Lead, Strategy Consulting at Trendline Interactive, where he focuses on creating messaging and segmentation strategies to drive maximum conversions while maintaining a strong focus on the optimal omni channel user experience. He has 13 years of email marketing and product management experience, creating and maintaining programs for both B2C and B2B audiences and overseeing everything from day-to-day campaign management to platform migrations. Scott graduated from The University of Iowa and lives outside of Chicago, Illinois with his wife and two children. Scott enjoys music, running, and fixing up old bikes in his spare time. Follow Scott on LinkedIn

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