Why are identified spam campaigns low in Google Postmaster compared to spam complaints?
Matthew Whittaker
Co-founder & CTO, Suped
Published 1 Jun 2025
Updated 17 Aug 2025
7 min read
It can be confusing when you dive into Google Postmaster Tools and notice a disparity: the overall spam complaint rate appears to be one thing, but the number of identified spam campaigns (those linked to specific Feedback Loop identifiers) seems surprisingly low in comparison. This observation isn't uncommon and points to a critical nuance in how Google reports spam data.
My experience, and that of many other email professionals, shows that Google Postmaster Tools offers a powerful, albeit aggregate, view of your sender reputation and deliverability at Gmail. However, interpreting the data, especially around spam complaints and identified campaigns, requires a deeper understanding of what each metric represents.
The perceived discrepancy between a high overall spam complaint rate and a low number of identified campaigns isn't a sign that the data is wrong. Instead, it highlights the different mechanisms Google uses to categorize and report unwanted email. Understanding these differences is crucial for effective deliverability management.
Understanding Google Postmaster Tools metrics
Google Postmaster Tools provides several dashboards, each offering a unique perspective on your email performance. The Spam Rate dashboard is perhaps the most critical for overall sender reputation. This metric reflects the percentage of your emails that Gmail users mark as spam, combined with emails that Gmail's internal algorithms automatically classify as junk.
It's a comprehensive figure that includes both active user complaints and system-detected spam. The ideal spam rate is below 0.1%, with a hard threshold at 0.3% before deliverability issues become severe. This dashboard gives you a holistic view of how your mail is perceived by Gmail recipients and its filters.
On the other hand, the Feedback Loop (FBL) Identifiers, often appearing in a separate section or within the Spam Rate dashboard details, provide a more granular insight. These identifiers (sometimes called Feedback-IDs) are custom tags that you, or your email service provider, add to your email headers. When a Gmail user explicitly clicks the 'Report spam' button, and your email includes a valid Feedback-ID, Google reports this specific complaint back to you, associated with that identifier. This allows you to pinpoint problematic campaigns or content.
The key difference lies in their scope: the overall spam rate includes all spam detections, while FBL identifiers only capture explicit user complaints for emails with the correct header. This explains why identified campaigns might seem low, even if the general spam rate is higher.
Reasons for the discrepancy
Several factors contribute to the observed gap between your total spam complaints (spam rate) and the reported identified campaigns via Feedback Loop. Firstly, not every email that ends up in the spam folder is a direct result of a user clicking the 'Report spam' button. Gmail's sophisticated filters play a significant role here, automatically routing suspicious emails to the spam folder based on numerous signals, such as sender reputation, content, authentication, and recipient engagement patterns.
Secondly, for an identified campaign to show up in the FBL section, your emails must contain a properly formatted Feedback-ID header. Many email senders, especially those not using a dedicated Email Service Provider (ESP) or those with older configurations, might not be including this header or might not be populating it correctly. If the header is missing or improperly configured, Google cannot attribute the complaint to a specific campaign identifier.
Furthermore, privacy considerations prevent Google from providing granular, user-level spam complaint data. The FBL provides aggregated data, and it's specifically designed to help high-volume senders identify problematic email streams, not individual user complaints. Therefore, the volume of data in the FBL section will naturally be lower and more focused than the broad spam rate.
Spam Rate Dashboard
Scope: Reflects all emails sent that Gmail users mark as spam or that Gmail algorithms filter into the spam folder.
Purpose: Provides an overall health check of your sender reputation and compliance with Google’s guidelines.
Actionability: Indicates if there's a general problem with your sending practices that needs investigation across your entire email program. Learn how to address sudden spikes.
Actionable steps to improve data and deliverability
Improving your domain reputation and getting more actionable insights from Google Postmaster Tools involves a multi-faceted approach. First, ensure that your email sending platform is correctly implementing the Feedback-ID header in your emails. This is crucial for Google to attribute spam complaints to specific campaigns.
The Feedback-ID header looks something like this in your email's raw source. Its value usually contains elements like your domain, a campaign identifier, and sometimes a user ID. This allows for post-delivery analysis of feedback loop spam rates.
Beyond technical setup, focus on fundamental email best practices. This includes maintaining a clean and engaged mailing list, sending relevant content that your subscribers expect, and avoiding misleading subject lines. Regularly cleaning your list of inactive subscribers and removing recipients who mark your emails as spam can significantly reduce your overall spam rate and help keep your domain off a blacklist or blocklist.
Also, understanding why your emails go to spam, even with a seemingly good reputation, is key. Factors such as content, engagement, and even the quality of your email list can influence deliverability independently of explicitly reported spam. Always monitor your blocklist status to ensure you're not on any major blacklists.
Navigating the data discrepancies
Spam rate dashboard
Data scope: Reflects both user-reported spam and algorithmic spam filtering by Gmail.
Granularity: Provides an aggregated percentage for your domain or IP, but doesn't typically break down by individual campaign (unless you also have FBL data populating for that campaign).
Indicator: A general health meter of your sender reputation. A consistently high rate suggests systemic issues.
Feedback loop identifiers
Data scope: Only includes Gmail users who explicitly click 'Report spam' on emails containing a valid Feedback-ID header.
Granularity: Allows you to identify specific campaigns or content that are generating user complaints, assuming your Feedback-ID is configured correctly.
Indicator: Helps pinpoint specific content or audience segments causing negative reactions.
Remember, the spam rate dashboard in Google Postmaster Tools reflects a broader measure of unwanted mail, including emails automatically filtered into the spam folder by Gmail's algorithms. The Feedback Loop identifiers, on the other hand, provide specific insights into campaigns that users have explicitly reported as spam.
If your identified spam campaigns are low, it could mean that while a general problem might exist (reflected in the overall spam rate), the explicit user complaints (the ones reported through FBL) are not yet tied to specific campaigns due to missing or incorrectly formatted Feedback-ID headers. It’s also possible that the data is still populating, especially if it’s a recent change or a new implementation, which is often the case with new features or Postmaster Tools V2 data.
The key is to proactively monitor both metrics. If your overall spam rate is high, even with low FBL identified campaigns, it's a strong signal to investigate your entire email program. This includes your list hygiene, content relevance, sending frequency, and overall engagement. Ultimately, a low spam rate (or blocklist rate) across all metrics is the goal for optimal email deliverability.
Views from the trenches
Best practices
Ensure your email service provider is correctly implementing and populating the Feedback-ID header in your outgoing emails. This is critical for Google Postmaster Tools to attribute spam complaints to specific campaigns and provide actionable insights.
Maintain a clean and engaged email list by regularly removing inactive subscribers and those who have previously marked your emails as spam. This practice improves overall deliverability and reduces the likelihood of being flagged as spam.
Align content with subscriber expectations: Send relevant and valuable content that your audience has opted-in to receive, avoiding misleading subject lines or overly promotional language that can trigger spam complaints.
Monitor both the overall spam rate and Feedback Loop identifiers in Google Postmaster Tools. A high overall spam rate, even with low identified campaigns, signals a broader deliverability issue that requires investigation beyond specific campaign complaints.
Common pitfalls
Not implementing the Feedback-ID header or populating it incorrectly. This prevents Google Postmaster Tools from providing granular insights into which specific campaigns are generating user-reported spam complaints, making it harder to diagnose issues.
Over-relying solely on Feedback Loop identifier data without considering the overall spam rate dashboard. The spam rate includes emails filtered by Gmail's algorithms, which might not show up in Feedback Loop data, leading to a false sense of security regarding deliverability.
Ignoring signs of low engagement or high bounce rates, which contribute to a poor sender reputation and can lead to emails being automatically filtered to spam, even if users aren't explicitly marking them as such.
Failing to segment your audience and personalize content, which often results in recipients marking emails as spam due to irrelevance or feeling bombarded with generic messages. This also contributes to poor
Expert tips
If you are seeing data in Postmaster Tools V2 that was not visible in V1, it indicates that Google has updated its reporting mechanisms. Adjust your monitoring strategy to utilize the new data available in V2 for more comprehensive insights.
Remember that Google Postmaster Tools does not explicitly share the percentage of emails automatically landing in the spam folder. You must infer this from other signals such as your overall spam rate, inbox placement testing, and engagement metrics to assess true deliverability.
When troubleshooting, check if your email marketing platform automatically populates the Feedback-ID header. If not, investigate how you can configure it, as this is essential for connecting user-reported spam to specific campaigns.
Be aware that privacy concerns mean Google will not provide user-level spam complaint data. Focus on aggregated trends and campaign-specific identifiers to understand broad patterns and areas for improvement.
Marketer view
Marketer from Email Geeks says they observed low identified spam campaigns compared to overall spam complaints, suggesting Google Postmaster Tools might still be populating data.
2024-12-12 - Email Geeks
Marketer view
Marketer from Email Geeks says they receive significantly more identifiers in Postmaster Tools v2 compared to v1.
2024-12-12 - Email Geeks
Putting it all together for better deliverability
The discrepancy between low identified spam campaigns and higher overall spam complaints in Google Postmaster Tools is a common observation. It highlights the difference between explicit user complaints on FBL-enabled campaigns and the broader spam classification performed by Gmail's algorithms.
By understanding these distinctions, properly implementing Feedback-ID headers, and focusing on overall email hygiene, you can gain more precise insights into your deliverability issues. This allows you to fine-tune your email strategy and ensure your messages consistently reach the inbox, rather than landing in the spam folder (or junk folder).
Google from providing granular, user-level spam complaint data. The FBL provides aggregated data, and it's specifically designed to help high-volume senders identify problematic email streams, not individual user complaints. Therefore, the volume of data in the FBL section will naturally be lower and more focused than the broad spam rate.
