Often used in Virus search results, a False Positive, also known as a false detection, occurs when an antivirus program detects a known virus string in an uninfected file.

In general a False Positive is a Type I error – the error of rejecting a null hypothesis when it is actually true. Plainly speaking, it occurs when we are observing an anomaly when actually there is none

A false positive is another way of saying ‘mistake’ and thus is also known as a ‘False Alarm’. In the field of anti-virus programming, a false positive occurs when the program mistakenly flags an innocent file as being infected. False positives can prove a nuisance in more ways than one:

• Productivity wasted due to user down-time
• Unnecessary security precautions
• Mindless security upgrades and backups to disinfect the seemingly ‘infected’ file
• Extra costs and time wastages due to above reasons

It also applies to anti-spam protection, where it refers to the misidentification of a legitimate e-mail message as spam. This too could be disastrous, since the undelivered e-mail may be an important business message.