Spam score
The number a filter assigns to a message from the tests it matched, compared with a threshold to decide whether the message is spam. Each filter has its own scale.
What it means
Scores are specific to each filter. In Apache SpamAssassin, every matching rule adds or subtracts points and a message is spam once the total reaches required_score, 5 by default and often set higher by ISPs. Microsoft stamps a spam confidence level from -1 to 9 and, for bulk mail, a bulk complaint level from 0 to 9.
A spam score from a testing tool therefore means one filter's verdict on one copy of your message. It is useful for spotting what triggers rules (missing authentication, a listed link domain, a broken HTML structure), but a low score does not predict placement at providers that weigh reputation and engagement.
Compare scores only within the same filter and configuration.
Related terms
On this site
Sources
What this definition rests on. The wording is ours; the facts are theirs.
- Apache SpamAssassin: Mail::SpamAssassin::Confspamassassin.apache.org
- Microsoft Learn: Spam confidence level (SCL)learn.microsoft.com
- Microsoft Learn: Bulk complaint level (BCL)learn.microsoft.com
All 432 terms in the glossaryThe wiki: blocklists and bounce codes