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Most marketers focus on open rates and click-through rates (CTR) when measuring email campaign success. But what if those numbers don’t tell the whole story?
Take Sarah, a marketing manager who was excited to see high open rates for her email campaigns. However, when she checked conversions, the results were disappointing. Despite crafting strong subject lines that got people to open her emails, her messages weren’t driving action.
The problem? She was missing key engagement metrics like click-to-open rate (CTOR) and read time, which offer deeper insights into whether recipients are actually engaging with the content or just skimming and moving on.
According to a report by HubSpot, email marketing has one of the highest ROIs in digital marketing, $36 for every $1 spent, but only when businesses track the right metrics. In this blog, we’ll explore the overlooked email KPIs that can help you refine your strategy, boost engagement and potentially double your conversions.
Many marketers rely on open rates and click-through rates (CTR) to measure email campaign success. While these metrics provide a surface-level view of performance, they often fail to reflect true engagement or intent.
One of the biggest issues with open rates is their inaccuracy due to Apple’s Mail Privacy Protection (MPP). With MPP preloading images, open rates can be artificially inflated, making it seem like more people are engaging with emails than they are. This means that optimising subject lines based on open rates alone may not lead to better conversions.
CTR also has its limitations. A high CTR might seem like a positive signal, but it doesn’t necessarily mean users are engaging meaningfully. Some recipients may click a link out of curiosity without reading the content, while others might misclick and bounce immediately, neither of which contributes to conversions.
By focusing only on open rates and CTR, marketers risk optimising for the wrong outcomes, missing deeper insights into engagement and user intent. Without tracking more meaningful engagement metrics, businesses could be leaving conversion opportunities on the table.
To truly optimise your email marketing performance, you need to go beyond open rates and CTR. By tracking deeper engagement metrics, you can gain a clearer picture of how recipients interact with your emails and uncover opportunities to improve conversions.
CTOR measures how many recipients who opened your email clicked on a link. Unlike CTR, which includes all recipients (even those who didn’t open the email), CTOR focuses only on engaged users, making it a more accurate measure of content effectiveness.
A good CTOR ranges between 10-15%, depending on the industry. If your CTOR is low, it likely means your content or call-to-action (CTA) isn’t compelling enough. To improve it, ensure that your email body delivers on the promise of your subject line and that CTAs are clear, action-driven and easy to find.
Read time measures how long recipients spend reading your email. This metric helps distinguish between users who genuinely engage and those who skim or immediately close the email.
A high read time suggests your content is relevant and engaging, while a short read time may indicate that your email is too dense, poorly formatted, or missing key information upfront. To improve dwell time, use clear formatting, concise paragraphs and engaging visuals to make your content easier to consume.
The number of replies and forwards is a powerful indicator of how valuable your emails are. A high reply rate suggests strong engagement and interest, while a high forward rate indicates that your content is useful enough for recipients to share with others.
Encouraging replies can be as simple as asking a direct question, such as “What’s your biggest challenge with [topic]?” Adding interactive elements like surveys or polls can also drive engagement.
Bounce rate measures how many of your emails fail to reach recipients' inboxes.
Regularly cleaning your email list and using double opt-in methods can help keep bounce rates low and maintain strong deliverability.
While unsubscribes are natural, tracking them alongside spam complaints is essential. A high spam complaint rate indicates that users didn’t expect or want your emails, which can damage your email reputation and lead to deliverability issues.
If unsubscribe rates are climbing, review your email frequency, content relevance and segmentation strategy to ensure you're targeting the right audience with the right messaging.
By monitoring these advanced KPIs, you’ll get a much clearer picture of email engagement, allowing you to fine-tune your strategy and maximise conversions.
Tracking advanced email KPIs isn’t just about collecting data; it’s about pinpointing where engagement drops and making the right adjustments to improve conversions. By analysing these deeper metrics, you can identify weak points in your campaigns and refine your email strategy for better performance.
If your click-to-open rate (CTOR) is low, it likely means your email content isn’t compelling enough to drive action. Improving email copy, visuals and CTA placement can make a huge difference. A more engaging subject line might get people to open your email, but a strong CTA ensures they take the next step.
A high bounce rate signals that your email list contains outdated or invalid addresses, which can negatively affect deliverability. Cleaning your email list regularly, removing inactive subscribers and using double opt-in verification can help keep your list healthy and engagement rates high.
If your email read times are short, it means recipients aren’t sticking around to absorb your content. Emails that are too long, poorly structured, or lack a clear takeaway often get skimmed and ignored. Restructuring your emails for skimmability, using concise paragraphs, bullet points and clear headings, can improve engagement.
A high spam complaint rate is a red flag that your email strategy needs adjustment. If too many users are marking your emails as spam, it could mean your frequency is too high, your subject lines are misleading, or your audience segmentation is off. Adjusting email frequency, refining your targeting and ensuring compliance with subscriber preferences can significantly reduce complaints and improve deliverability.
Every small tweak, whether it's better formatting, smarter segmentation, or stronger CTAs, can drive meaningful improvements in engagement and conversions, making your email campaigns far more effective.
To track these advanced email KPIs effectively, leveraging the right tools is essential. Standard email metrics like open rates and CTRs are easy to monitor, but tracking deeper engagement requires more robust analytics platforms.
HubSpot and Mailchimp provide detailed engagement insights, including click maps that show where recipients are interacting with your emails. These tools help you understand which parts of your email are most engaging and where users drop off.
Google Analytics is a powerful way to track post-click email performance. By integrating UTM parameters into your email links, you can see exactly how email-driven traffic behaves on your website, including bounce rates, time spent on a page and conversion actions.
Litmus and Email on Acid offer insights into email read time and device-specific engagement, helping you understand how different audiences interact with your emails. These tools are especially useful for optimising mobile responsiveness and ensuring that emails are easy to read across different screen sizes.
By setting up UTM parameters, marketers can accurately attribute website conversions back to specific email campaigns, helping refine strategies based on real engagement data. When used effectively, these tools provide a complete picture of email performance, allowing businesses to fine-tune their approach for maximum impact.
At Mr Digital, we’ve seen firsthand how tracking the right engagement metrics can transform campaign performance. A great example is our work with Pad Creative, a London-based branding and design agency looking to attract more qualified leads.
Their initial ad campaigns were struggling to generate high-quality conversions due to broad targeting and ineffective keyword strategies. By fine-tuning their approach, we implemented precise audience segmentation, refined ad copy and optimised keyword targeting, which resulted in:
This case study highlights the importance of tracking and refining engagement metrics, whether in email campaigns or paid advertising. Just as optimising Pad Creative’s ad strategy led to improved conversions, applying advanced KPIs like CTOR, email read time and reply rates can help businesses improve email performance and maximise results.
Relying only on open rates and CTR provides an incomplete picture of email performance. While these metrics indicate initial engagement, they don’t reveal whether subscribers are truly interested or just skimming through. By tracking advanced email KPIs such as click-to-open rate (CTOR), email read time and reply rates, businesses can gain deeper insights into subscriber behaviour and refine their strategy to drive higher conversions.
Every small improvement, from better audience segmentation to more engaging email copy and optimised CTAs, adds up to significant results. Just like we’ve seen in real-world case studies, fine-tuning email performance based on meaningful engagement metrics can turn a good campaign into a great one.
Need help optimising your email marketing strategy? Let’s refine your reporting to uncover hidden conversion opportunities and maximise your results. Contact us today!
Joshua is a Senior Content Writer with a diverse background in journalism and storytelling. He has a passion for crafting engaging and informative content that resonates with target audiences. Joshua's experience in writing and his understanding of digital marketing ensure content is both captivating and effective in achieving marketing goals.
Shiyas brings years of experience in digital marketing to his role as Client Success Director. He has a proven track record of developing and executing successful strategies across various online channels, with a focus on driving business growth and exceeding client expectations.
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