Why is SenderScore showing inaccurate data or low scores?
Matthew Whittaker
Co-founder & CTO, Suped
Published 4 Aug 2025
Updated 15 Aug 2025
6 min read
SenderScore, provided by Validity, is a well-known metric that assesses the reputation of an IP address on a scale of 0 to 100. It aims to reflect how mailbox providers view your sending habits. A high score suggests you are a trustworthy sender, while a low score can indicate potential deliverability issues, often leading to emails landing in spam folders or being rejected outright.
However, it is not uncommon for senders to observe SenderScore displaying inaccurate data or unexpectedly low scores. This can be a source of confusion and concern, especially when internal metrics suggest healthy sending practices. Several factors contribute to these discrepancies, ranging from how the score is calculated to external influences beyond your immediate control.
Understanding why these inaccuracies occur is crucial for effective email deliverability management. While SenderScore provides valuable insights, relying solely on this one metric can lead to misinterpretations and misguided strategies. It is essential to combine this information with other data points for a comprehensive view of your email program's health.
How SenderScore works and why it can appear inaccurate
Understanding SenderScore's limitations
SenderScore gathers data from a variety of sources, including spam trap hits, complaints, unsubscribes, bounces, and engagements across their network. The algorithm processes this data over a 30-day rolling average to generate your IP's reputation score. While comprehensive, this methodology has inherent limitations that can lead to perceived inaccuracies or low scores, even for otherwise healthy senders.
Key factors contributing to low scores
One primary reason for fluctuating or low scores is the weight given to different data points. For instance, some internet service providers (ISPs) that contribute data to SenderScore might disproportionately impact the overall score if they experience a backlog of data or unusual traffic patterns. This can temporarily skew your reputation, even if your direct sending performance remains strong.
Additionally, the proprietary nature of SenderScore's algorithm means the exact weighting and impact of each factor are not publicly disclosed. This lack of transparency can make it challenging to pinpoint the precise reason for a score drop. It means that what you perceive as a minor issue might be heavily weighted by their system, leading to a significant score reduction.
Furthermore, the score is primarily IP-based. If you use a shared IP address, the sending behavior of other users on that same IP can affect your SenderScore. Even if your own practices are stellar, another sender's poor reputation can drag down the collective score, inadvertently impacting your deliverability. This is why many high-volume senders opt for dedicated IP addresses.
Addressing data discrepancies and volume issues
Several critical factors commonly lead to a low SenderScore, even if your delivery rates appear high initially. These factors are closely monitored by mailbox providers and directly influence your IP and domain reputation.
High spam complaint rates are a major red flag. When recipients mark your emails as spam, it signals to ISPs that your content is unsolicited or undesirable. Even a small percentage of complaints can significantly harm your sender reputation and, consequently, your SenderScore. This is often a stronger indicator of poor sending practices than bounce rates.
Engagement metrics also play a significant role. If your emails have low open rates or click-through rates, or if recipients frequently delete your emails without opening them, it can negatively impact your score. This signals to mailbox providers that your content is not engaging or relevant to your audience, which can lead to filtering. Conversely, high engagement contributes to a positive reputation.
Common issues
Data lag: SenderScore's 30-day rolling average can cause delays in reflecting current sending behavior, leading to scores that lag behind your actual performance.
Shared IP impact: The actions of other senders on your shared IP can negatively affect your score, regardless of your own practices.
Volume misclassification: Low-volume senders might be incorrectly categorized as high-volume, impacting how their data is interpreted by the algorithm.
Solutions and mitigations
Diverse monitoring: Supplement SenderScore with other reputation tools, Google Postmaster Tools, and direct feedback loops to get a holistic view.
Dedicated IPs: If sending volume is sufficient, consider a dedicated IP to have full control over your sending reputation.
Proactive outreach: Contact SenderScore support directly if you suspect significant data inaccuracies or misclassifications.
Actionable steps to improve your reputation
Sometimes, SenderScore data can appear inaccurate due to processing delays or backfills of information, particularly from large ISPs like Comcast. These backfills can cause sudden drops or increases in your score as historical data is integrated into the rolling average. This means your score might be reflecting past issues, or issues related to large, delayed data processing, rather than your current performance.
For low-volume senders, SenderScore may sometimes show incorrect volume classifications, marking an IP as high volume when it is not. This can impact the score's accuracy because the algorithm might be applying high-volume reputation criteria to a low-volume sender, leading to a disproportionately low score. This is a known challenge for smaller senders relying on such broad reputation metrics.
If you notice your SenderScore dropping despite consistent, good sending practices, it is worthwhile to investigate if large data backfills or volume misclassifications are at play. While you cannot directly control these external factors, understanding them can help you contextualize the data and avoid unnecessary alarm. It also highlights the need for broader monitoring.
Factor
Impact on SenderScore
Mitigation
Data backfills
Can cause sudden, temporary drops or increases reflecting delayed data processing.
Monitor trends, not just daily fluctuations. Contact SenderScore support if sustained.
Shared IP usage
Other senders' poor reputation can drag down your score.
Ensure your ESP has robust anti-abuse policies. Consider a dedicated IP.
Volume misclassification
Low volume IPs can be incorrectly marked as high volume, leading to disproportionate score impacts.
Focus on high-quality engagement and maintain consistent sending patterns.
If your SenderScore is low or appears inaccurate, there are several proactive steps you can take to diagnose and improve your overall email reputation. The first step is to avoid panic and look beyond a single metric.
Review your email list hygiene rigorously. High bounce rates, especially to invalid or stale addresses, are detrimental. Implement a strict list cleaning process to remove inactive or problematic contacts. Regularly check for signs of spam traps which can disproportionately harm your reputation, often leading to your IP being placed on a blocklist or blacklist.
Ensure your email authentication protocols are correctly configured. SPF, DKIM, and DMARC are fundamental to proving legitimate email origins. Errors in these settings can lead to emails being flagged as suspicious, irrespective of content quality. Use tools to verify their correct implementation.
Example DMARC record to start monitoring email authenticationDNS
Regularly clean your email lists to remove inactive or bouncing addresses. This minimizes spam trap hits and improves overall engagement metrics.
Implement robust email authentication (SPF, DKIM, DMARC) to prove the legitimacy of your emails and build trust with mailbox providers.
Focus on sending highly engaging content to genuinely interested subscribers to reduce complaint rates and increase positive engagement.
Diversify your reputation monitoring by using multiple tools and direct feedback loops from major ISPs, not just SenderScore.
Common pitfalls
Relying solely on SenderScore as the definitive measure of your email reputation, ignoring other crucial deliverability metrics.
Neglecting list hygiene, which leads to high bounce rates, spam trap hits, and ultimately a lower sender reputation.
Ignoring email authentication, making your emails appear less trustworthy and more susceptible to spam filtering by ISPs.
Not understanding that shared IP addresses can be affected by the sending practices of other users, regardless of your own quality.
Expert tips
Investigate any sudden, unexplained drops in SenderScore by checking for large ISP data backfills or volume misclassifications.
For low-volume senders, focus on maintaining very high engagement and low complaint rates to offset potential volume misinterpretations by reputation systems.
When troubleshooting, look for patterns in your sending data over time rather than focusing on isolated daily fluctuations in your score.
Engage with the email community and forums to gain insights into widespread issues or known reporting delays from reputation services.
Marketer view
Marketer from Email Geeks says SenderScore was appearing broken, with low bounce rates showing as low scores in the 60s and 70s for sender rejected emails.
2019-12-27 - Email Geeks
Marketer view
Marketer from Email Geeks says some low volume IPs, averaging below 100,000 emails per week, were being incorrectly marked as high volume.
2019-12-27 - Email Geeks
Beyond the score: a holistic view of email reputation
While SenderScore is a widely recognized metric for email reputation, it is crucial to remember it is one data point among many. Inaccuracies or low scores can stem from a variety of sources, including algorithm complexities, data backfills, shared IP addresses, and low sending volume misclassifications. By adopting a holistic approach to email deliverability, focusing on strong authentication, rigorous list hygiene, and consistent engagement, you can build a robust sending reputation that transcends any single score.
Comcast. These backfills can cause sudden drops or increases in your score as historical data is integrated into the rolling average. This means your score might be reflecting past issues, or issues related to large, delayed data processing, rather than your current performance.
