You cannot improve what you do not measure. Email analytics transform email from a black box into a data-driven channel where you can see what works, identify problems, and continuously optimize performance.
This guide covers the essential email metrics, how tracking technology works, privacy considerations, and how to build an analytics-driven email program.
Essential Email Metrics
Delivery Metrics
Delivery Rate
The percentage of emails accepted by receiving servers. Formula: (Sent - Bounces) / Sent * 100. Target: Greater than 98%. This measures whether your emails reach the mail server, not the inbox.
Bounce Rate
The percentage of emails that bounced. Track hard bounces (permanent failures, target less than 0.5%) and soft bounces (temporary failures, target less than 2%) separately.
Complaint Rate
The percentage of recipients who marked your email as spam. Formula: Complaints / Delivered * 100. Target: Less than 0.1%. This is critical for reputation.
Engagement Metrics
Open Rate
The percentage of recipients who opened the email. Formula: Opens / Delivered * 100. Note that open tracking has become less reliable since iOS 15 Mail Privacy Protection pre-loads tracking pixels.
Click Rate
The percentage of recipients who clicked a link. Formula: Clicks / Delivered * 100. More reliable than opens as it requires actual user action.
Click-to-Open Rate (CTOR)
The percentage of openers who clicked. Formula: Clicks / Opens * 100. This measures content effectiveness among engaged recipients.
Conversion Metrics
Conversion Rate
The percentage who completed the desired action. Formula: Conversions / Clicks * 100 or Conversions / Delivered * 100. Requires integration with your analytics or backend.
Revenue Per Email
Revenue attributed to email divided by emails sent. Critical for e-commerce. Requires proper attribution tracking.
How Email Tracking Works
Open Tracking
A tiny, invisible image (1x1 pixel) is embedded in the email. When the email is opened and images load, the pixel is requested from the tracking server, which logs the open event including timestamp, IP address, user agent, and email ID.
Open Tracking Limitations
- Images must load (many clients block by default)
- Apple Mail Privacy Protection pre-fetches pixels
- Text-only readers cannot trigger pixels
- Multiple opens may be one person checking multiple times
Click Tracking
Original links are replaced with tracking URLs that redirect through the email provider's servers. When clicked, the tracking server logs the click, records metadata, and redirects to the original URL.
Click tracking is more reliable than open tracking because it requires deliberate user action.
Privacy Considerations
Apple Mail Privacy Protection
Since iOS 15 and macOS Monterey, Apple Mail can pre-load remote content including tracking pixels, mask IP addresses, and report opens even when the user has not actually opened the email. This affects roughly 50% of email opens depending on your audience.
Impact on Metrics
- Open rates are inflated for Apple Mail users
- Open-based segmentation becomes unreliable
- Send-time optimization based on opens is compromised
- Click metrics remain reliable
Adapting Your Strategy
- Weight click metrics more heavily than opens
- Use conversion tracking for meaningful engagement
- Consider opens as a directional indicator, not absolute truth
- Segment by device or client when possible
Building an Analytics Dashboard
Key Views
Overview Dashboard
Display send volume over time, delivery rate trend, bounce and complaint rates, and overall engagement rates.
Campaign Performance
Compare performance across different email types with delivery metrics, engagement metrics, and conversion attribution.
Health Monitoring
Show bounce rate by type, complaint rate trend, delivery issues by ISP, and suppression list growth.
Alerting
Set up alerts for delivery rate dropping below 95%, hard bounce rate exceeding 0.5%, complaint rate exceeding 0.1%, and sudden engagement drops.
Advanced Analytics
Cohort Analysis
Track subscriber behavior over time. How do engagement patterns change as subscribers age? Which acquisition sources produce the most engaged users?
A/B Testing Analytics
Systematically test subject lines, send times, content variations, and from names. Ensure statistical significance before drawing conclusions.
Attribution Modeling
Understand how email contributes to conversions. Consider last-click attribution, multi-touch attribution, and time-decay models.
Using Analytics to Improve
Identifying Problems
- Delivery rate dropping: Check authentication, reputation, content
- High bounces: Review list sources, implement validation
- Low opens: Test subject lines, sender name, send time
- Low clicks: Improve content, CTAs, design
- High unsubscribes: Review frequency, content relevance
Continuous Improvement Loop
- Measure current performance
- Identify areas for improvement
- Hypothesize and test changes
- Measure impact
- Implement winners, iterate on losers
Conclusion
Email analytics provide the feedback loop necessary for continuous improvement. Focus on metrics that matter for your business, understand the limitations of tracking technology, and use data to drive decisions rather than gut feelings.
GetMailer provides comprehensive analytics including real-time delivery tracking, engagement metrics, and ISP-level insights. Our dashboard makes it easy to monitor email health and identify opportunities for improvement.