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How accurate is Microsoft SNDS data for deliverability monitoring?

Summary

Experts, marketers, and Microsoft's own documentation suggest that SNDS data provides a directional overview of deliverability, but it's not an absolute measure. SNDS functions independently from Outlook's spam filters and might not capture all spam trap hits. Data is often lagged and may differ from other ISPs' assessments. For small senders SNDS is less statistically relevant. A holistic approach using SNDS alongside other tools (e.g., Google Postmaster Tools, Litmus), focusing on long-term trends, correlating data with bounce rates and engagement, and proactively addressing feedback (e.g., cleaning lists) is recommended.

Key findings

  • Directional Indicator: SNDS provides a directional overview, not absolute truth, for deliverability.
  • System Independence: SNDS operates separately from Outlook's spam filters, creating potential inconsistencies.
  • Data Latency: SNDS data is not real-time and often lagged, affecting immediate responsiveness.
  • Incomplete Data: SNDS may not capture all spam trap hits, especially from private networks.
  • Limited Scope: JMRP data relies on user participation and doesn't represent the entire user base.
  • Sender size matters: For small volume senders, SNDS might lack statistical significance.

Key considerations

  • Holistic Approach: Use SNDS with other deliverability tools for a comprehensive understanding.
  • Trend Analysis: Focus on identifying long-term trends rather than individual data points.
  • Data Correlation: Correlate SNDS data with bounce rates, engagement, and suppression lists.
  • Proactive Action: Act on feedback, cleaning lists, segmenting, and improving content engagement.
  • Understand Limitations: Recognize that SNDS provides one perspective and has limitations; consider external reputation data.

What email marketers say

10 marketer opinions

Experts and marketers generally agree that Microsoft SNDS data should be viewed as a directional indicator rather than an absolute source of truth for deliverability. Discrepancies exist between SNDS data and actual inbox placement, especially for small volume senders. Various factors, including data latency, spam trap variations, and audience engagement, impact SNDS accuracy. Utilizing SNDS in conjunction with other deliverability tools like Google Postmaster Tools and internal metrics is recommended. Acting on feedback from SNDS, such as addressing high complaint rates and cleaning email lists, is crucial.

Key opinions

  • Directional Indicator: SNDS data is more useful as a trend indicator rather than a precise measure of deliverability.
  • Data Discrepancies: SNDS data can be out of sync with actual inbox placement rates.
  • Small Volume Limitations: SNDS data may not be statistically significant for small volume senders.
  • Context Matters: Interpreting SNDS data requires understanding the context of your email program and audience.

Key considerations

  • Use in Conjunction: Use SNDS with other deliverability tools (e.g., Google Postmaster Tools, Litmus) for a comprehensive view.
  • Act on Feedback: Take action based on SNDS feedback, such as cleaning lists and segmenting audiences.
  • Monitor Trends: Focus on analyzing trends over time, rather than individual data points.
  • Correlate with Metrics: Correlate SNDS data with bounce rates, suppression lists, and engagement metrics.

Marketer view

Email marketer from StackOverflow answers that interpreting SNDS data requires understanding the context of your email program and audience. Sudden spikes in complaints could be due to a specific campaign or list quality issues.

16 Feb 2025 - StackOverflow

Marketer view

Email marketer from NeilPatel.com shares that SNDS data should be viewed as directional indicators rather than absolute truth. High complaint rates warrant investigation, but don't always indicate a severe problem, especially if volume is low.

26 Apr 2023 - NeilPatel.com

What the experts say

3 expert opinions

Experts indicate that Microsoft SNDS has limitations as a deliverability monitoring tool. It operates separately from Outlook.com's spam filters, leading to potential discrepancies between SNDS reports and actual inbox placement. SNDS data might not capture all spam trap hits, and the information is often lagged, hindering real-time response to deliverability issues. Differences in complaint calculation between ISPs and ESPs further complicate the accuracy of SNDS for precise monitoring.

Key opinions

  • Separate System: SNDS functions independently from Outlook.com's spam filters, causing potential inconsistencies.
  • Incomplete Spam Trap Data: SNDS might miss spam trap hits from private networks, making a clean report unreliable.
  • Data Lag: SNDS data is often delayed, hindering immediate reaction to deliverability changes.
  • Calculation Differences: ISPs and ESPs calculate complaint rates differently, affecting data interpretation.

Key considerations

  • Broad Strokes Monitoring: Use SNDS for general oversight, but not for precise deliverability assessment.
  • Supplement with Other Tools: Do not rely solely on SNDS; use other monitoring methods to get a comprehensive view.
  • Understand Data Limitations: Recognize the limitations of SNDS data, including data lag and potential inaccuracies.
  • Focus on Trends: Look for overall trends rather than relying on single data points.

Expert view

Expert from Word to the Wise answers that the data in SNDS is known to be lagged (often by a few days), so it doesn't necessarily give you an immediate picture of your current sending reputation or any sudden changes. This can be problematic if you're trying to react quickly to deliverability issues.

29 Jan 2024 - Word to the Wise

Expert view

Expert from Email Geeks explains that SNDS is a wholly separate system from the actual spam filters inside of Outlook.com. It can be useful for broad strokes monitoring, but it is not uncommon to have a red result in SNDS but mail still delivers to the inbox, or vice versa. Complaint rates can be useful directionally, but sender and receiver calculations often differ, with ISPs counting complaints on the date of the complaint and ESPs rolling it back to the send date.

19 Aug 2024 - Email Geeks

What the documentation says

4 technical articles

Microsoft's documentation states that SNDS aims to provide data on sending IP addresses, including complaint rates and spam trap hits, to help address deliverability issues. However, it also acknowledges that SNDS data is not real-time and has latency, impacting its immediacy. Furthermore, the accuracy of JMRP data depends on user participation and may not represent the entire user base. The IP reputation metrics reflect Microsoft's assessment, which might differ from other ISPs.

Key findings

  • Intended Use: SNDS provides data on sending IP addresses, complaint rates, and spam trap hits for identifying deliverability issues.
  • Data Latency: SNDS data is not real-time; there is a delay between events and their reflection in SNDS.
  • JMRP Accuracy: JMRP data accuracy relies on user participation and may not represent the entire user base.
  • Reputation Assessment: IP reputation metrics reflect Microsoft's assessment, which may differ from other ISPs.

Key considerations

  • Understand Limitations: Acknowledge the limitations of SNDS data, including latency and potential inaccuracies.
  • Consider User Participation: Recognize that JMRP data reflects the actions of participating users, not the entire audience.
  • Account for ISP Differences: Be aware that Microsoft's IP reputation assessment may differ from other ISPs.
  • Use for Directional Insight: Use SNDS as one source of data to understand deliverability and look at it directionally.

Technical article

Documentation from Microsoft clarifies that the IP reputation metrics in SNDS reflect Microsoft's assessment of your sending practices. This assessment might differ from how other ISPs view your reputation.

6 Sep 2023 - Microsoft

Technical article

Documentation from Microsoft notes that SNDS data isn't real-time. There's often a delay between when an event occurs (e.g., a user marks an email as spam) and when it's reflected in SNDS. This latency can affect the immediacy of the data's usefulness.

2 Feb 2022 - Microsoft

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