Summary
A compliant user-reported spam rate can give a deceptively positive impression of email deliverability. While a low complaint rate is often seen as a good sign, it frequently masks underlying issues. The primary reason for this is that emails landing directly in the spam folder are typically not seen by recipients, preventing them from being reported. Furthermore, many users choose to delete, ignore, or unsubscribe from unwanted emails rather than actively marking them as spam. Internet Service Providers (ISPs) also employ sophisticated internal filtering systems and rely on a broader set of metrics, including engagement levels, bounce rates, and spam trap hits, to determine inbox placement. Consequently, emails can be silently filtered or blocked without generating a user complaint, rendering the reported spam rate an incomplete and potentially misleading indicator of true deliverability.
Key findings
- Silent Filtering: Internet Service Providers (ISPs) frequently filter emails directly to the spam folder or block them based on internal algorithms, sender reputation, and recipient engagement, without recipients ever seeing or manually reporting them as spam.
- User Behavior: Many recipients opt to ignore, delete, or unsubscribe from unwanted emails instead of actively marking them as spam, leading to artificially low complaint rates that do not reflect actual dissatisfaction.
- Incomplete FBLs: Feedback Loops (FBLs) only capture a subset of user complaints because not all mailbox providers offer them, providing an incomplete and potentially misleading view of actual complaint volume.
- Broader Reputation Factors: Deliverability is determined by numerous factors beyond direct spam reports, including engagement metrics, bounce rates, spam trap hits, and overall sender reputation, which can lead to poor inbox placement even with low user complaints.
- Spam Trap Impact: Hitting spam traps severely damages sender reputation and deliverability, yet these incidents do not generate any user-reported spam complaints, giving a false sense of security.
- Low Volume Effect: A low complaint rate might simply reflect low email volume rather than robust inbox placement, as fewer emails naturally result in fewer opportunities for complaints.
Key considerations
- Analyze Engagement: Prioritize monitoring engagement metrics like opens and clicks, as these provide a more accurate picture of inbox placement and recipient interest.
- Historical Trends: Examine past complaint rate drops; these could indicate a shift towards spam folder delivery rather than improved user satisfaction.
- Comprehensive Monitoring: Look beyond Feedback Loops and user complaints to assess deliverability by tracking bounces, spam trap hits, and overall sender reputation, which are crucial for ISPs.
- Audience Segmentation: Focus on sending valuable content to engaged subscribers to gradually improve sending statistics and rebuild a positive reputation with mailbox providers.
- Easy Unsubscribe: Ensure a clear and easily accessible unsubscribe option to reduce frustration-driven spam reports, as users may report spam if they cannot find a way to opt-out.
- Holistic View: Understand that a low complaint rate alone does not guarantee good deliverability; it is merely one metric among many that ISPs consider.
What email marketers say
9 marketer opinions
A user-reported spam rate, while seemingly intuitive, often presents a deceptive picture of email deliverability. This metric alone is insufficient because it fails to capture the significant volume of emails silently filtered into spam folders by Internet Service Providers (ISPs) based on complex algorithms, sender reputation, and overall recipient engagement, without any direct user action. Additionally, recipient behavior such as simply deleting unwanted messages, overlooking a difficult-to-find 'report spam' button, or general apathy can lead to artificially low complaint numbers. Critical issues like hitting spam traps or the negative impact of list decay also go unreported by users, yet severely damage sender reputation. Consequently, a low reported spam rate can mask serious deliverability problems, underscoring the need for a more comprehensive assessment that incorporates engagement metrics and ISP filtering nuances.
Key opinions
- ISP Silent Filtering: Many emails are automatically directed to the spam folder by Internet Service Providers (ISPs) based on internal algorithms, sender reputation, and engagement, without the recipient ever seeing or manually reporting them as spam.
- Engagement Overrides Complaints: Poor sender reputation is often more closely tied to low open rates and other engagement metrics over time than to consistently high user-reported spam rates.
- Unreported Spam Traps: Hitting spam traps, which are unmonitored email addresses used by ISPs to identify spammers, severely damages deliverability but does not generate user complaints.
- Recipient Apathy & Behavior: Many users delete, ignore, or don't explicitly report unwanted emails as spam due to apathy, difficulty in finding the report button, or misunderstanding its purpose, leading to underreported issues.
- List Decay Impact: Sending to abandoned or unmonitored email addresses due to list decay negatively affects sender reputation and deliverability, yet these instances rarely result in direct user complaints.
- Holistic Reputation: A low spam complaint rate is just one signal; ISPs consider a broad range of metrics including opens, clicks, bounces, and spam trap hits, meaning low engagement can still signal a problem even with few complaints.
Key considerations
- Prioritize Engagement: Focus on improving engagement metrics, especially opens, as they are a strong indicator of inbox placement and a key factor for mailbox providers.
- Segment Engaged Users: To rebuild reputation, identify and target segments of your audience that still show engagement, gradually improving sending statistics.
- Monitor Diverse Metrics: Look beyond user-reported spam rates to include engagement, bounce rates, and spam trap monitoring for a more accurate deliverability assessment.
- Simplify Unsubscribe: Ensure a clear and easy unsubscribe process to reduce instances where users might report spam out of frustration rather than genuine content disapproval.
- Address List Hygiene: Implement strategies to combat list decay and proactively remove unengaged or invalid addresses to avoid hitting spam traps and maintain sender reputation.
- Interpret Complaints Broadly: Understand that a low complaint rate doesn't automatically mean good deliverability, and user 'spam' reports can stem from various reasons, not just content quality.
Marketer view
Marketer from Email Geeks shares that he rarely observes consistently high complaint rates for domains with a bad reputation, except for occasional large spikes, reinforcing the idea that low complaint rates can be misleading for domains facing deliverability issues.
25 Mar 2025 - Email Geeks
Marketer view
Marketer from Email Geeks explains that in his experience, most bad sender reputations result from poor open rates over time, rather than high spam rates directly, though high spam rates can precede low engagement. He advises that to improve deliverability when stuck in the spam folder, marketers should identify and focus on sending valuable content to segments of subscribers who still show engagement (opens) to gradually rebuild positive sending statistics with mailbox providers like Gmail.
17 Sep 2024 - Email Geeks
What the experts say
3 expert opinions
A seemingly low user-reported spam rate can be highly deceptive for gauging email deliverability. This metric alone often fails to reflect the true picture because emails frequently land in the spam folder without ever being seen or reported by recipients. Moreover, subscriber behavior often leans towards ignoring, deleting, or moving unwanted messages rather than actively marking them as spam. Internet Service Providers (ISPs) also employ advanced, hidden filtering mechanisms that divert or block emails based on a wide array of signals-such as sender reputation, content, and engagement-even before a user has the opportunity to lodge a complaint. Therefore, a minimal complaint rate can wrongly suggest good inbox placement, masking significant deliverability challenges.
Key opinions
- Spam Folder Invisibility: Emails delivered directly to the spam folder are often unseen by recipients, eliminating opportunities for user complaints and artificially lowering the reported spam rate.
- Beyond User Complaints: Internet Service Providers (ISPs) use a diverse array of internal filtering mechanisms, including sender reputation, content analysis, and engagement signals, to determine inbox placement, independent of direct user spam reports.
- Non-Reporting User Actions: Many recipients deal with unwanted emails by deleting, ignoring, or moving them without explicitly marking them as spam, meaning low complaint rates do not fully capture recipient dissatisfaction.
- Low Volume Distortion: An extremely low complaint rate, such as 0.01% to 0.02%, might simply reflect a low volume of sent emails rather than robust deliverability, as fewer emails naturally yield fewer opportunities for complaints.
- Historical Rate Drops: Sudden decreases in user-reported spam rates could indicate a shift towards messages landing in the spam folder, rather than an improvement in audience satisfaction or content relevance.
- Incomplete Feedback Loops: Spam rates reported via Feedback Loops (FBLs) only represent a subset of potential complaints and do not account for all negative recipient interactions or ISP filtering decisions.
Key considerations
- Monitor Engagement Closely: Prioritize analyzing engagement metrics such as open and click rates, as these provide a more accurate signal of actual inbox placement and subscriber interest than reported spam rates.
- Examine Historical Trends: Investigate past declines in complaint rates, as these may signal a change in deliverability where emails began to bypass the inbox and land directly in the spam folder.
- Comprehensive Deliverability Audit: Adopt a holistic view of deliverability by assessing metrics beyond user complaints, including bounces, spam trap hits, and overall sender reputation, which are critical for ISP evaluation.
- Facilitate Easy Opt-Out: Provide a clear, highly visible unsubscribe option to ensure frustrated recipients can easily opt out, reducing the likelihood of them resorting to reporting messages as spam.
- Understand ISP Filtering: Recognize that Internet Service Providers (ISPs) utilize complex, automated filtering systems that can divert or block emails based on numerous factors before any user interaction, making direct complaints only one piece of the puzzle.
- Contextualize Low Rates: Be aware that a very low reported spam rate, particularly with low sending volumes, does not automatically signify excellent deliverability; it requires deeper analysis in conjunction with other metrics.
Expert view
Expert from Email Geeks explains that a lack of complaints is often a sign of spam folder delivery, not good deliverability. He suggests that if emails are going directly to the spam folder, users won't see them to report, resulting in a low complaint rate. He advises looking for when complaint rates historically dropped, as that might correlate with emails starting to land in the spam folder.
19 Feb 2024 - Email Geeks
Expert view
Expert from Spam Resource explains that a low user-reported spam rate, such as 0.01% or 0.02%, can be misleading because it doesn't automatically guarantee strong deliverability. While these rates are conventionally considered good, they don't account for other crucial factors like low email volume, which can naturally result in fewer complaints. Furthermore, ISPs employ various internal filtering mechanisms and metrics beyond direct user complaints to determine message placement, meaning emails could be filtered to the spam folder or blocked entirely even if not explicitly marked as spam by the recipient.
16 Feb 2025 - Spam Resource
What the documentation says
5 technical articles
A seemingly compliant user-reported spam rate can create a false sense of security regarding email deliverability. This metric is often insufficient because it only accounts for active user complaints, failing to capture numerous other critical factors. For instance, not all mailbox providers offer Feedback Loops, leading to an incomplete view of overall complaints. Many recipients also prefer to simply delete, ignore, or unsubscribe from unwanted emails rather than actively marking them as spam, meaning low complaint numbers might not reflect true dissatisfaction. Crucially, a low complaint rate entirely overlooks instances where emails are blocklisted or silently rejected by Internet Service Providers (ISPs) before reaching the inbox or even the spam folder, thereby preventing any user reporting. ISPs utilize a broad range of signals-including engagement, bounces, and direct IP/domain blocks-to determine sender reputation, making a low complaint rate only one piece of a much larger, complex deliverability puzzle.
Key findings
- Partial Complaint Visibility: A significant portion of user complaints goes unrecorded because not all mailbox providers offer Feedback Loops, resulting in an incomplete view of your actual spam rate.
- Non-Reporting User Behavior: Subscribers often opt to delete unwanted messages or unsubscribe rather than actively reporting them as spam, meaning a low complaint rate doesn't necessarily reflect high satisfaction or engagement.
- Misleading Signal of Health: While a low complaint rate (e.g., below 0.1%) is often seen as good, it only accounts for active user reports and fails to capture other critical negative signals that harm deliverability, such as low engagement or spam trap hits.
- Comprehensive ISP Reputation Factors: Sender reputation, critical for inbox placement, is determined by Internet Service Providers (ISPs) using a much broader set of metrics beyond user complaints, including email volume, bounce rates, direct IP/domain blocks, and overall recipient engagement.
- Silent Rejection via Blocklisting: If an IP or domain is blocklisted by an Internet Service Provider (ISP), emails may be silently rejected before reaching the inbox, thus generating no user-reported complaints despite a severe deliverability issue.
Key considerations
- Broaden Deliverability Metrics: To gain an accurate understanding of deliverability, look beyond just user complaints and actively monitor a wider range of metrics, including open rates, click-through rates, bounce rates, and any blocklisting notifications.
- Decipher User Non-Action: Recognize that a low spam complaint rate might indicate user apathy or a preference for deletion or unsubscribing, rather than active engagement or satisfaction with your content.
- Proactively Monitor Blocklists: Regularly check your sender IP and domain against common blocklists. Blocklisting leads to silent rejections and severely impacts deliverability without generating any user-reported spam data.
- Prioritize Engagement Insights: Focus on engagement metrics like open and click rates, as they offer more reliable insights into inbox placement and subscriber interest than a low user-reported spam rate alone.
Technical article
Documentation from SparkPost Documentation explains that a low complaint rate reported via Feedback Loops (FBLs) might be misleading because not all mailbox providers offer FBLs, meaning you only get visibility into a subset of actual complaints. This lack of universal FBL coverage can give a falsely optimistic view of your overall complaint rate.
29 Apr 2022 - SparkPost Documentation
Technical article
Documentation from MailerLite Knowledge Base explains that many users prefer to simply delete unwanted emails or ignore them rather than actively reporting them as spam. They might also choose to unsubscribe instead of marking as spam, especially if the unsubscribe link is easily visible. This means a low spam complaint rate doesn't necessarily indicate high engagement or satisfaction, but rather a lack of strong negative action.
26 Jan 2025 - MailerLite Knowledge Base
Are spam complaint rates siloed by provider affecting deliverability?
How can spam complaints and bad content choices impact email deliverability?
How do spam reports affect email domain reputation and deliverability?
Why are Google Postmaster Tools spam rates inaccurate?
Why is Google Postmaster Tools spam rate higher than ESP reported spam rate?
Why is my spam complaint rate so high during email warm-up?
