Summary
Seed lists are a foundational tool for assessing email deliverability, yet their results often diverge significantly from organic engagement data. This discrepancy can be perplexing for email marketers and deliverability professionals alike, leading to confusion and potentially misdirected optimization efforts. The core reason for this difference lies in how mailbox providers, such as Gmail and Outlook, evaluate incoming mail. Organic engagement data reflects real user behavior, including opens, clicks, and replies, which are strong positive signals. Seed list addresses, by nature, are automated accounts that do not engage with emails, thus lacking these crucial positive signals. This fundamental difference means seed tests often represent a more pessimistic scenario, especially for disengaged subscribers, while organic data reflects the true inbox placement for engaged users.
Key findings
- Engagement gap: Seed list addresses do not engage with emails, which can lead to poorer inbox placement results compared to organic sends that benefit from high user engagement.
- Mailbox provider algorithms: Mailbox providers heavily factor in recipient engagement when determining inbox placement, a signal missing from seed tests. This is why you might see a 60%+ open rate organically, but seeds go to spam.
- Pessimistic scenario: Seed lists often indicate the deliverability performance for non-engaged or cold segments of your list, rather than the overall performance.
- Context is key: Seed test results should always be interpreted within the broader context of your organic email engagement data. For more on this, read our article how accurate are seed lists.
Key considerations
- Holistic view: Combine seed list testing with real-time engagement metrics, complaint rates, and bounce data for a comprehensive deliverability picture.
- Identify issues: While seed lists might show a worst-case scenario, consistent spam placement across seeds can signal underlying issues with your sending reputation or content, which might worsen with repeated testing.
- Provider-specific nuances: Microsoft (Outlook/Hotmail) is particularly sensitive to individual user engagement, making seed test results to these providers highly variable and often poorer than organic. Certified Senders Alliance shares limitations of seed data to consider.
- Targeting optimization: Seed lists can be valuable for predicting deliverability to unengaged segments or for validating new subscriber deliverability and win-back campaigns.
What email marketers say
Email marketers often find themselves in a tricky spot when seed list results don't align with their actual campaign performance. The prevailing sentiment is that while seed lists are a useful tool for a preliminary check, they do not fully capture the nuanced dynamics of real-world inbox placement. Marketers frequently observe vastly different outcomes, with seed tests showing spam placement while their live campaigns achieve high engagement and inboxing rates. This highlights the importance of not relying solely on seed data for a complete understanding of deliverability performance. Instead, marketers advocate for integrating seed list insights with direct engagement metrics, especially for new subscriber segments or re-engagement efforts.
Key opinions
- Incomplete picture: Seed lists offer limited insight into true campaign deliverability, as they cannot replicate the complex engagement signals of live subscribers.
- Organic data rules: Real-time engagement stats (like opens and clicks) are considered far more indicative of actual inbox placement for active subscribers than seed test results.
- New subscriber barometer: Seed lists are more reliable for gauging how new or unengaged subscribers might receive mail, helping with deliverability for new subscribers.
- Confirmation tool: If seed tests show 100% inboxing, it strongly suggests any deliverability issues are not due to general spam filters, but perhaps engagement metrics are declining.
Key considerations
- Don't panic: Low seed test results should prompt a check of organic engagement data before making drastic campaign changes.
- Layer data: Always cross-reference seed results with metrics like opens, clicks, unsubscribes, and spam complaints to understand overall performance, especially if email clicks are declining.
- Weather prediction analogy: Consider seed tests like a weather prediction, useful but not always perfectly accurate, requiring ongoing monitoring. Bookyourdata also notes that while seed lists are useful for confirming deliverability of marketing emails, they only provide initial indications.
- Specific use cases: Use seed tests to monitor deliverability for specific list segments, such as newly acquired subscribers or those you're trying to re-engage, where organic signals might be weaker.
Marketer view
Marketer from Email Geeks shared a recent experience where Google and Outlook seed addresses went to spam, despite the live campaign showing 60%+ open rates on Gmail and 40%+ on Outlook, with no negative engagement spikes. This highlights the occasional misleading nature of seed tests compared to organic data.
Marketer view
Email marketer from Email Geeks states that seed tests are helpful within the context of understanding organic data too. It's crucial not to rely on them in isolation.
What the experts say
Deliverability experts generally agree that seed lists serve a specific, but not exhaustive, purpose. Their main utility lies in providing a pessimistic view of deliverability, particularly for less engaged recipients. Experts emphasize that seed accounts inherently lack the positive engagement signals (opens, clicks, replies) that real subscribers provide. This absence causes them to often land in spam, even when organic campaigns are highly successful. Therefore, the key is to understand the limitations and interpret seed results as one data point among many, especially distinguishing between how providers like Gmail versus Microsoft handle engagement signals.
Key opinions
- Non-engaging nature: Seeds are typically non-engaging, representing a worst-case scenario for deliverability (e.g., if you were to mail to inactive users).
- Engaged vs. disengaged: High open rates on organic sends indicate effective targeting of engaged users who are likely inboxing, while seeds highlight placement for disengaged segments.
- Contextual interpretation: Seed test results are clues that all signals may not be strong enough for even disengaged users, rather than a definitive statement on overall inboxing. This explains why deliverability differs across providers.
- Microsoft sensitivity: Microsoft's dynamic, user-level placement makes their seeds much more prone to spam unless all macro signals (engagement, bounces, complaints, spam traps) are impeccable.
Key considerations
- Nuance is vital: A deeper understanding of seed testing's nuances is crucial due to the lack of context provided by some tools.
- Complementary data: Always combine seed list data with your actual platform metrics and engagement rates to get an accurate picture.
- Focus on engagement: Prioritize strategies that boost real user engagement, as this is the strongest signal for inbox placement, especially when dealing with the consequences of unengaged subscribers.
- Provider differences: Be aware that different mailbox providers (ISPs) have varying algorithms, meaning a seed test that performs well for one ISP might not for another. Word to the Wise details the difference between inbox and delivery.
Expert view
Expert from Email Geeks notes that seed lists primarily represent a pessimistic scenario. This means that if you were to email non-openers, they would likely receive mail in spam, contrasting with engaged targeting, where users are likely inboxing.
Expert view
Expert from Email Geeks suggests that a misleading seed test result doesn't mean all engaged users are in spam. Instead, it indicates that perhaps not all signals are consistently positive enough to ensure inboxing for even disengaged users.
What the documentation says
Official documentation and research often highlight the distinction between email delivery and inbox placement. While seed lists primarily confirm delivery to an address, they don't comprehensively assess inbox placement in the main folder versus spam. Mailbox providers' algorithms are sophisticated, relying heavily on real-time engagement metrics, sender reputation, and complaint rates. Documentation consistently points out that positive user interaction is a paramount signal. Since seed lists cannot replicate this interactive behavior, their results inherently lack this crucial dimension, leading to discrepancies when compared to live campaign data.
Key findings
- Engagement signals: Mailbox providers prioritize engagement metrics, such as opens and clicks, as key indicators of wanted mail. Seeds do not provide these signals.
- Sender reputation: A sender's reputation (IP and domain) is built over time through consistent positive engagement, low bounce rates, and minimal spam complaints. Seed tests are only one factor in this complex calculation.
- Algorithmic complexity: ISPs use advanced algorithms that adapt to user behavior and sender patterns, which static seed lists cannot fully account for. Running a deliverability test checklist helps.
- Spam trap avoidance: While seed lists can help detect technical blockages, they don't entirely simulate the impact of hitting spam traps, which significantly degrade sender reputation.
Key considerations
- Focus on deliverability factors: Understand that true deliverability success comes from a combination of technical setup (SPF, DKIM, DMARC), content quality, and consistent positive engagement.
- Monitor broader metrics: Don't just look at seed inboxing rates; complement them with actual open rates, click-through rates, complaint rates, and bounce rates for a complete picture. Consider technical solutions from top performing senders.
- User experience: Optimize campaigns for genuine user experience and value, as this drives engagement and positive reputation, ultimately leading to better inbox placement.
- Ongoing adaptation: Recognize that mailbox provider algorithms evolve, requiring continuous monitoring and adaptation of sending practices beyond what static seed lists can inform.
Technical article
Documentation from Certified Senders Alliance states that while seed data offers initial indications, it provides only very limited insights into a campaign's true deliverability because it lacks the crucial element of real user engagement.
Technical article
Documentation from Kickbox Blog suggests that many email deliverability metrics are often misunderstood, emphasizing that true inbox placement hinges on factors beyond simple seed testing, such as long-term sender reputation and active engagement.
Related resources
14 resources
Related pages
How accurate are seed lists for email deliverability testing?
How do deliverability seed list tools like eDS EVUN and 250Ok Seedlist Optimizer function?
How does repeated seed testing impact email deliverability accuracy and reputation monitoring?
Why are emails to new subscribers going to spam while existing list deliverability remains good?
Why am I still having deliverability issues after cleaning my email list?
What are the deliverability consequences of decreasing email metrics due to sending to unengaged subscribers?
Should email seed lists be sent separately from regular email sends?
How accurate are email verification services when subscriber engagement contradicts their findings?
Why does email deliverability differ across mailbox providers?
Why your emails are going to spam in 2024 and how to fix it
