Do ISPs differentiate between single and bulk spam reports when evaluating email sender reputation?

Email marketer from Litmus shares that its best to send emails at a good sending cadence and frequency that users will remember, but not be spammed by. If users are marked as spam it will lower the senders reputation.

Email marketer from Mailjet explains that user engagement signals are crucial. High engagement with previous emails from a sender will likely reduce the impact of a single spam report from that user.

Email marketer from MarketingProfs explains that ISPs consider the source and frequency of spam complaints. A sudden spike from one user might trigger scrutiny, while consistent reports from diverse users hold more weight.

Email marketer from Email on Acid shares that ISPs factor in user engagement. If a user suddenly marks a large number of emails from a previously engaged-with sender as spam, the ISP might consider the context.

Email marketer from Stack Overflow shares that ISPs also use spam traps and other methods to evaluate senders, in addition to user complaints. They mention high complaint rates coupled with hitting spam traps hurts reputation more.

Email marketer from Reddit shares that ISPs likely have algorithms to detect and weigh spam reports differently based on the source. A single user marking many emails as spam may be less impactful than multiple users reporting individually.

Email marketer from Sendgrid states that quality of emails must be high. Following this will reduce the chance of users marking as spam due to confusing emails or users unsure who the email is from.

Email marketer from Gmass shares that having good list hygiene is important so less chance of users marking as spam. Also notes, users who don't remember signing up may mark as spam so its better to email recently active users.

Expert from Email Geeks shares that while ISPs don't explicitly state whether they discount spam reports when a user reports hundreds of emails at once, they do send the reports. He assumes these reports count unless proven otherwise.

Expert from Email Geeks shares her gut feeling is ISPs don’t necessarily evaluate old reports the same as recent complaints, based on a past interaction with AOL. She suspects there is a cutoff for the age of an email and its impact on reputation but states it's speculation.

Expert from Word to the Wise explains that high complaint rates are a sign that your mail stream is not being well received and you should investigate this. Email senders should look at complaint rates to investigate delivery issues.

Expert from Word to the Wise explains that complaint feedback loops (FBLs) provide data to senders. Some FBLs provide aggregate counts while others provide individual reports. The aggregate reports will still factor complaints towards sender reputation whereas individual ones provide insight into what caused it.

Documentation from RFC Editor discusses message format. While not directly addressing spam reports, it explains the underlying standards used by ISPs to analyze email content, context and origins which is used in conjunction with spam reports.

Documentation from Google explains that they monitor spam rates and user feedback, suggesting they analyze reports beyond just the sheer number and likely consider the source and user history.

Documentation from AWS SES explains how complaints are measured, a high spam complaints rate can affect your account. They will monitor and may even block senders who do not follow best practices.

Documentation from Spamhaus is an organisation which lists bad senders. They state that if there is high number of complaints with a sender from users or due to bad sending practices they are more likely to be listed by them.

Documentation from Microsoft's Smart Network Data Services (SNDS) details how they track complaint rates and sender reputation, implying they differentiate between various types of spam reports.