The singular term false positive is a term used in the software development industry to refer to a Type-1 error which your antivirus software may claim has occurred. A Type-1 error simply means that your antivirus software thinks there is a virus in your software application when in fact there is none. A Type-1 error is categorized as a failure of detection event. So the term “positives” means that there are real errors or real viruses within your software application.
The counter-term to the false positive is the false negative term which is used to describe a failure by your antivirus program to detect a real infection by a real virus. This amounts to a Type-II error which is more serious than a false positive claim by your program (but both are considered problems in using the antivirus program of your computer.)
A false positive crops up when the scan string that the antivirus program used was also found in the object that it thought was a virus (but which was actually not.) You face more serious problems when you get a false negative because viruses are becoming more and more complicated which is why they may pass scrutiny by your existing anti-virus software.
There are such things as ghost positives: this means that when the antivirus program was trying to disinfect your software application, there was a segment of the virus which was retained in the target location (but which is not actually harmful because the virus code is no longer intact.) When another antivirus program passes through the same location, it might spot the remaining virus code segment and call it an infection or a positive. Such positives will not harm your computer but are a nuisance anyway. Ghost positives may be retained in what is called slack space in your disk space; this indicates space which may be used by files but which is presently empty. Any ghost positives should eventually disappear when defragmentation is conducted by optimization programs that can remove virus segments from your slack space.
It is also possible to come by a positive in another way: your program reports that there is one type of virus that exists in your computer when in reality that is another type of virus altogether. Thus, when a virus cure is applied for the virus that you thought existed, it may create problems for you such as loss of extended divisions or a disk that cannot be read.
Generic disinfection or disinfecting your files regardless of what type of virus is supposed to be there may also create problems for you like rendering valuable files unusable. If you want to spend on them, there are better generic disinfection programs that can protect the data on your affected files.
Thus, a positives service level agreement can be said to be a formal agreement between the developer of an antivirus program and the end user of the program concerning the presence of positives when the antivirus program is run on your computer.