What Does Bayesian Filter Mean?
A Bayesian filter is a computer program using Bayesian logic or Bayesian analysis, which are synonymous terms. It is used to evaluate the header and content of email messages and determine whether or not it constitutes spam – unsolicited email or the electronic equivalent of hard copy bulk mail or junk mail). A Bayesian filter is best used along with anti-virus programs.
Techopedia Explains Bayesian Filter
A Bayesian filter works with probabilities of specific words appearing in the header or content of an email. Certain words indicate a high probability that the email is spam, such as Viagra and refinance. The filter does not start out knowing the likelihood that a word indicates a high probability of spam. Users must manually identify the email as spam. When enough occurrences of the word are found and the email is identified as spam, the Bayesian filter “learns” to identify the word using likelihood functions. It does the same with many other words and phrases. Over time, the Bayesian filter becomes more and more effective at identifying spam for a particular user. When the probability reaches a certain threshold, such as 95 percent, then the email is identified as spam and often moved to a junk folder (or sometimes even deleted automatically). The user can periodically view it and decide whether or not to delete it. Alternately, some spam programs will move it to a quarantine location where users can view the email and review the software’s decision.
