Summary
The consensus is that pruning email lists generally helps deliverability. Removing unengaged, inactive, or invalid subscribers improves sender reputation by signaling to ISPs that you are sending mail only to interested recipients, reduces bounce rates and spam complaints, and focuses efforts on engaged contacts. However, experts caution against overly aggressive strategies based solely on opens and clicks, as this can inadvertently remove active but unmeasured subscribers. Best practices include using historical data for informed pruning decisions, implementing re-engagement campaigns before permanent removal, prioritizing the removal of invalid addresses, and aligning segmentation and pruning strategies with the type of email being sent.
Key findings
- Sender Reputation Improvement: Pruning improves sender reputation by demonstrating engagement to ISPs, leading to better deliverability.
- Reduced Bounce Rates & Spam Complaints: List hygiene reduces bounce rates and spam complaints, both of which negatively impact deliverability.
- Focus on Engaged Contacts: Pruning allows for concentrated efforts and resources on engaged subscribers, improving ROI and campaign effectiveness.
- Mail Client Metrics vs. Sender Metrics: Mail client engagement metrics (e.g., opens) can differ from sender-tracked metrics, requiring caution when assessing engagement.
- Importance of List Hygiene: Regular list hygiene, including removing invalid addresses, is crucial for maintaining deliverability.
Key considerations
- Avoid Overly Aggressive Pruning: Pruning strategies based solely on opens and clicks can remove engaged subscribers due to factors like image blocking or alternative reading methods (e.g., RSS readers).
- Data-Driven Decisions: List pruning should be based on historical recipient behavior and data analysis rather than arbitrary cutoff points.
- Re-engagement Campaigns: Implement re-engagement campaigns to win back non-responders before permanently removing them from the list.
- Segmentation and Email Type: Segmentation strategies and pruning frequency should be aligned with the purpose and type of email being sent (e.g., less aggressive pruning for newsletters).
- Subscriber Lifecycle Management: A holistic subscriber lifecycle management approach, including win-back campaigns and prompt handling of unsubscribe requests, is essential for long-term deliverability.
What email marketers say
14 marketer opinions
Pruning your email lists is generally considered beneficial for deliverability. Removing unengaged subscribers improves sender reputation, reduces bounce rates and spam complaints, and focuses efforts on engaged contacts. This practice signals to ISPs that you're sending emails to interested recipients, increasing inbox placement rates. However, pruning should be done carefully, considering the type of email being sent and potential impact on active but unmeasured subscribers.
Key opinions
- Sender Reputation: Pruning improves sender reputation by demonstrating engagement to ISPs.
- Reduced Bounces & Complaints: List hygiene lowers bounce rates and spam complaints, positively impacting deliverability.
- Focus on Engaged Contacts: Pruning allows for concentrated efforts and resources on engaged subscribers, improving ROI.
- Improved Inbox Placement: A clean list increases the likelihood of emails landing in the inbox rather than spam folders.
- Re-engagement Window: The likelihood of re-engaging users decreases significantly after 122 days of inactivity.
Key considerations
- Segmentation Strategy: Segmentation for pruning should align with email purpose (e.g., less aggressive for newsletters).
- Active vs. Measured Engagement: Be cautious not to remove active subscribers who may not be engaging in measurable ways (e.g., image blocking).
- Re-engagement Campaigns: Implement re-engagement campaigns before permanently removing subscribers.
- Prompt Unsubscribes: Always honor unsubscribe requests promptly, regardless of perceived engagement.
- List Type: Approaches to pruning may differ for marketing emails versus newsletters.
Marketer view
Email marketer from Sendinblue shares that pruning inactive subscribers enhances engagement rates, which mailbox providers use to assess sender reputation, directly impacting deliverability and inbox placement.
6 Sep 2024 - Sendinblue
Marketer view
Marketer from Email Geeks shares an unpublished study, revealing the likelihood of re-engaging users decreases significantly beyond 122 days of inactivity. They advise initiating re-engagement efforts between 60-90 days and pruning after 120 days.
7 Oct 2022 - Email Geeks
What the experts say
4 expert opinions
Experts generally agree that list pruning can help deliverability, but caution against overly aggressive strategies based solely on opens and clicks. Mail client engagement metrics often differ from what senders track, potentially leading to the removal of active users. They suggest using historical data for informed pruning, prioritizing the removal of invalid addresses and managing spam complaints. A key aspect of this is a subscriber lifecycle management approach, using win-back campaigns to re-engage non-responders before complete removal.
Key opinions
- Differing Metrics: Mail client engagement metrics and sender metrics can differ, leading to inaccurate engagement assumptions.
- Data-Driven Decisions: List pruning should be based on historical recipient behavior rather than arbitrary cutoff points.
- Subscriber Lifecycle: Managing non-responders through win-back campaigns is essential before removing them.
- Essential Hygiene: Removing invalid addresses and managing spam complaints are key components of list hygiene.
Key considerations
- Avoid Aggressive Pruning: Pruning strategies based solely on opens and clicks can remove engaged subscribers.
- Image Blocking: Consider the impact of image blocking on open rates when assessing engagement.
- Engagement Lags: Implement a strategy to handle subscribers with engagement lags before removing them.
- Prioritize Invalid Addresses: Focus on removing invalid addresses and managing spam complaints for deliverability.
Expert view
Expert from Email Geeks advises against arbitrary cutoff points for list pruning, suggesting using historical recipient behavior data to make informed decisions.
12 Oct 2024 - Email Geeks
Expert view
Expert from Email Geeks warns that mail client engagement metrics differ from what senders see and removing subscribers based on opens or clicks can remove active readers who won't harm deliverability.
15 Jan 2024 - Email Geeks
What the documentation says
4 technical articles
Email marketing documentation consistently highlights the importance of pruning email lists for improved deliverability. Regularly cleaning lists of unengaged, inactive, or invalid subscribers helps maintain a healthy list, reduces bounce rates and spam complaints, and improves sender reputation with major inbox providers like Gmail and Outlook. This practice ensures that emails are delivered to active and engaged recipients, minimizing the risk of being flagged as a spammer and maximizing inbox placement.
Key findings
- Healthy List: Regularly cleaning email lists maintains a healthy subscriber base.
- Reduced Bounce Rates: Pruning helps in reducing bounce rates, signaling better list quality to ISPs.
- Fewer Spam Complaints: A clean list leads to fewer spam complaints, a key factor in sender reputation.
- Improved Sender Reputation: Sending to engaged users improves sender reputation with major providers like Gmail and Outlook.
- Enhanced Inbox Delivery: List hygiene ensures emails are more likely to land in the inbox rather than spam.
Key considerations
- Regular Maintenance: Email list pruning should be a routine practice, not a one-time event.
- Inactive Subscribers: Focus on removing subscribers who haven't engaged in a defined period.
- Invalid Addresses: Prioritize the removal of invalid email addresses (hard bounces) to avoid deliverability issues.
- Compliance: Ensure pruning practices comply with email marketing regulations (e.g., GDPR, CAN-SPAM).
Technical article
Documentation from SparkPost shares that a key factor in maintaining good deliverability is regular list hygiene, including removing inactive or invalid email addresses to avoid being flagged as a spammer.
24 Mar 2023 - SparkPost
Technical article
Documentation from Google Postmaster Tools indicates that maintaining a clean email list with engaged users is crucial for ensuring your emails are delivered to Gmail inboxes, avoiding spam filters.
31 Mar 2022 - Google
Are email list cleaning services useful for improving email deliverability, and how do they work?
Do email list cleaning services effectively remove spam traps?
How can I accurately verify my email list and identify potentially harmful domains?
How can I identify and remove email addresses submitted via list bombing?
How can I prevent fake email addresses from being added at checkout and causing hard bounces?
How do email database cleaning services remove waste and invalid addresses?
How do I target inactive email users without hurting my domain reputation?
How do I validate email addresses and maintain a clean email list?
How long should I exclude unengaged email subscribers to improve deliverability?
