Bayesian filter


(bā´ zē-en fil´tër) (n.) A technique for identifying incoming e-mail spam. Unlike other filtering techniques that look for spam-identifying words in subject lines and headers, a Bayesian filter uses the entire context of an e-mail when it looks for words or character strings that will identify the e-mail as spam. Another difference between a Bayesian filter and other content filters is that a Bayesian filter learns to identify new spam the more it analyzes incoming e-mails.

Bayesian filtering is named for English mathematician Thomas Bayes, who developed a theory of probability inference. Bayesian filtering is predicated on the idea that spam can be filtered out based on the probability that certain words will correctly identify a piece of e-mail as spam while other words will correctly identify a piece of e-mail as legitimate and wanted. At its most basic level, a Bayesian filter examines a set of e-mails that are known to be spam and a set of e-mails that are known to be legitimate and compares the content in both e-mails in order to build a database of words that will, according to probability, identify, or predict, future e-mails as spam or not. Bayesian filters examine the words in a body of an e-mail, its header information and metadata, word pairs and phrases and even HTML code that can identify, for example, certain colors that can indicate a spam e-mail.

Bayesian filters are adaptable in that the filter can train itself to identify new patterns of spam and can be adapted by the human user to adjust to the user��s specific parameters for identifying spam. Bayesian filters also are advantageous because they take the whole context of a message into consideration. For example, not every e-mail with the word “cash” in it is spam, so the filter identifies the probability of an e-mail with the word “cash” being spam based on what other content is in the e-mail.

Proponents of Bayesian filters assert that the filters return less than one percent of false positives.

Other forms: Bayesian filtering (v.)

Read Also:

  • auto focus

    Abbreviated as AF, auto focus is a function of a digital camera in which the camera automatically focuses on the subject in the center of the LCD or viewfinder. Digital cameras come standard with auto focus, and more expensive models, or those considered professional digital cameras, will have the option to select the auto focus […]

  • BeanShell

    A free embeddable Java source interpreter with object scripting language features that is written in Java. BeanShell can dynamically execute standard Java syntax and extends Java syntax with common scripting conveniences such as loose types, commands and method closures like those in Perl and JavaScript. Since BeanShell is small and embeddable developers can call BeanShell […]

  • Bell 103

    The de facto standard protocol in the United States for transmitting data over telephone lines at transmission rates of 300 baud. The Bell 103A standard defines asynchronous, full-duplex communication. Europe and Japan use the CCITT V.21 protocol.

  • Bell 212A

    The de facto standard protocol in the United States for transmitting data over telephone lines at transmission rates of 1,200 bps. The Bell 212A standard defines asynchronous, full-duplex communications. Europe and Japan use the CCITT V.22 protocol.

  • BenQ

    Named one of the Top 100 IT companies in BusinessWeek three years in a row, BenQ has manufacturing plants in China, Taiwan, Malaysia and Mexico. Formerly Acer Communications & Multimedia, the name BenQ was adopted in December 2001. BenQ’s product lines are managed by four business groups: Imaging Network (scanners, optical drives, digital cameras, color […]


Disclaimer: Bayesian filter definition / meaning should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. All content on this website is for informational purposes only.