Learn how to identify and fix drops in key email performance metrics (KPIs) such as delivery rate, opens, clicks, conversions, and revenue to maintain strong deliverability and campaign performance.
Why your email KPIs matter
Key performance indicators (KPIs) help you understand how effectively your email and messaging strategy is performing.
Common KPIs include:
Delivery rate
Open rate
Click rate
Conversion rate
Revenue from email
List growth rate
A decline in any of these metrics can impact your overall results and may signal issues with deliverability, targeting, or content strategy.
Start here: Identify where the drop is happening
Before taking action, determine which metric is declining:
Lower deliveries → possible list or deliverability issue
Lower opens → subject line, targeting, or reputation issue
Lower clicks → content or CTA issue
Lower conversions → landing page or offer issue
Lower revenue → combination of all above
Once identified, use the sections below to troubleshoot effectively.
1. If the delivery rate is decreasing
Your delivery rate reflects how many emails successfully reach inboxes.
Common causes:
High bounce rates
Poor list quality
Irregular sending patterns
Over-emailing subscribers
What to do:
Clean your email list regularly
Remove invalid or inactive contacts
Maintain a consistent sending cadence
Avoid sending too frequently to the same audience
If the delivery rate drops below expected levels, focus on list hygiene first before anything else.
2. If open rates are declining
Open rate measures how many recipients actually view your emails.
Common causes:
Weak or repetitive subject lines
Sending to unengaged audiences
Email fatigue (too frequent sends)
Deliverability issues
What to do:
Improve subject lines (clear, relevant, engaging)
Segment and target engaged users
Adjust sending frequency
Test different send times
Consistently low opens may also indicate sender reputation issues, so monitor deliverability closely.
3. If click rates are dropping
Click rate shows how effective your email content is in driving action.
Common causes:
Lack of compelling offers
Repetitive or irrelevant content
Broken or missing links
Poor mobile or desktop rendering
What to do:
Use clear and strong CTAs
Refresh your content and creative regularly
Ensure all links are working correctly
Optimize emails for both mobile and desktop
Always include one primary CTA to guide user action clearly.
4. If conversion rates are decreasing
Conversion rate reflects how many users complete a desired action (e.g., purchase).
Common causes:
Weak landing page experience
Irrelevant targeting
Pricing or offer changes
Poor checkout experience
What to do:
Ensure email links lead to high-intent pages (product pages, not just homepage)
Optimize your checkout flow
Use abandoned cart or browse abandonment journeys
Align offers with audience segments
Even small friction in the buying journey can significantly impact conversions.
5. If list growth is slowing
List growth impacts your ability to scale revenue over time.
Common causes:
Low-performing signup forms
Weak incentives
Reduced acquisition efforts
What to do:
Optimize signup forms by clearly communicating value (discounts, early access, etc.).
Test placement and timing of forms
Improve messaging and CTAs
Strong list growth ensures a steady flow of new engaged subscribers.
6. If revenue is declining
Revenue is influenced by multiple KPIs working together.
Diagnose using these scenarios:
Scenario 1: Same traffic, lower order value
Customers are spending less per order
Action:
Introduce upsell/cross-sell strategies
Promote higher-value products
Scenario 2: Same traffic, lower conversions
Users aren’t completing purchases
Action:
Improve landing pages and checkout
Strengthen offers and messaging
Scenario 3: Lower traffic
Fewer users are reaching your website
Action:
Increase campaign frequency (strategically)
Leverage multiple channels (email, SMS, social)
Run re-engagement campaigns
Additional checks to consider
If KPIs drop unexpectedly, also review:
Changes in your sending strategy
Recent campaign or template updates
Tracking issues (UTMs, analytics tools)
Integration or data syncing issues
How this connects to deliverability
Many KPI declines—especially opens and deliveries—are closely tied to deliverability.
To maintain strong performance:
Keep your list clean
Send to engaged audiences
Maintain consistent sending behavior
Ensure proper authentication setup
You can also refer to your deliverability and authentication guides to rule out technical issues.
Key takeaway
Declining KPIs are not random—they’re signals.
Identify the metric that dropped
Diagnose the root cause
Take targeted action
Fixing the right issue early helps you maintain strong deliverability, better engagement, and consistent revenue from your email program.