(Mis)Classifications and Sidelining

Before we go any further, we should talk about misclassified messages. In a perfect world, spam wouldn’t exist, and no legitimate messages would be misclassified as spam. However, we live in an imperfect world, so we must deal with spam and messages that get routed to our spam folder incorrectly.

A false positive is a legitimate message that is incorrectly identified as spam. Most anti-spam implementations try to minimize false positives because they are messages that recipients may not see if they don’t check their junk email folder often enough. A false negative is a spam message that ends up in a user’s regular inbox. These are usually more acceptable because the recipient won’t be as likely to miss a message ...

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