With open rates now unreliable, marketers need a smarter way to evaluate email performance. The good news is that there are far better indicators of real engagement and revenue. These five metrics give you a clearer picture of how your emails work and what to improve.
1. CTR (click-through rate)
CTR shows whether your content can motivate people to take action. It reveals the level of interest, clarity of the message, and its relevance.
An improvement in CTR usually indicates that your copywriting, bid value, and visual guidance of the user are working correctly.
2. CTOR (click-to-open rate)
CTOR shows how strong the message itself is after the user opens it.
This metric eliminates noise caused by unreliable open measurement and focuses on whether the email actually met the expectations created by the subject line and preview text.
3. Conversion rate
Clicks are not the goal. Conversions are.
The conversion rate shows how many visitors from the email completed the desired action—a purchase, registration, or other conversion.
This metric links email to real business results.
4. Revenue per email
One of the most powerful metrics.
RPE tells you how much each email sent earns on average and helps you determine which campaigns are most valuable.
RPE also allows for a fair comparison of campaigns and segments, as it removes the bias caused by different numbers of recipients.
5. Engagement decay
This metric shows how quickly new subscribers lose interest. If they stop clicking within a few weeks, it's a sign that the onboarding or overall content strategy needs to be adjusted.
Monitoring engagement decay will help you know when to launch reactivation campaigns or when to reduce frequency.
Summary: focus on impact, not impressions
The success of email marketing is no longer about how many people opened the email.
It's about who took action, who converted, and who remains active in the long term.
Measure metrics that predict growth and true value.
Everything else is just noise.
