False positives, untimely filtering of legitimate e-mails

Definition and functioning of a false positive

What is a false positive?

Definition: a false-positive email is a legitimate email that is marked as spam or rejected by spam filtering or security filters. False-positive emails can be annoying for users as they may miss important or urgent emails.

How does false-positive detection work?

False-positive email detection is carried out by spam or security filters that use algorithms to determine whether an email is legitimate or not. The algorithms use a variety of techniques to analyse the e-mail, including analysis of the e-mail header, analysis of the e-mail content and analysis of the sender’s behaviour.

The false positive rate is the percentage of legitimate e-mails wrongly identified as spam by anti-spam. False-positive and false-negative rates are measures of the quality of an antispam solution. The lower these rates are, the better the solution performs. However, these two rates always vary inversely. Altospam favours reducing the more damaging false-positive rate as much as possible, which is why it is very close to zero.

Glossaire Définition Faux positif

Mailsafe Altospam applications

ALTOSPAM filters spam with a near-zero false-positive rate (less than 0.1%). We consider it preferable to receive the occasional spam message, although ALTOSPAM’s false-negative rate is more than respectable, rather than blocking legitimate emails and generating false-positives. On the other hand, ALTOSPAM manages false-positive cases, by informing as many interested parties as possible: the sender (by giving him the option of releasing his email via a Turing test), the administrator (via an online administration console) and the recipient (via a log mail summarizing the list of previously blocked messages).

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