"Triage" is a medical term. It refers to dividing wounded or sick people into three categories: those who will die no matter what you do, those who will recover even if unaided, and those who will recover only if aided. In a situation where there's too much to do, you must concentrate on the third group.
Bug Triage Meetings (sometimes called Bug Councils) are project meetings in which open bugs are divided into categories. The most important distinction is between bugs that will not be fixed in this release and those that will be
There are three categories for the medical usage, software also three categories - bugs to fix now, bugs to fix later, and bugs we'll never fix
Triaging a bug involves:
Making sure the bug has enough information for the developers and makes sense
Making sure the bug is filed in the correct place
Making sure the bug has sensible "Severity" and "Priority" fields
Let us see what Priority and Severity means
Priority is Business;
Severity is Technical
In Triages, team will give the Priority of the fix based on the business perspective. They will check “How important is it to the business that we fix the bug?” In most of the times high Severity bug is becomes high Priority bug, but it is not always. There are some cases where high Severity bugs will be low Priority and low Severity bugs will be high Priority.
In most of the projects I worked, if schedule drawn closer to the release, even if the bug severity is more based on technical perspective, the Priority is given as low because the functionality mentioned in the bug is not critical to business.
Priority and Severity gives the excellent metrics to identify overall health of the Project. Severity is customer-focused while priority is business-focused. Assigning Severity for a bug is straightforward. Using some general guidelines about the project, testers will assign Severity but while assigning a priority is much more juggling act. Severity of the bug is one of the factors for assigning priority for a bug. Other considerations are might be how much time left for schedule, possibly ‘who is available for fix’, how important is it to the business to fix the bug, what is the impact of the bug, what are the probability of occurrence and degree of side effects are to be considered.
Read the excellent article Arguing Apples and Oranges
This article clearly explains the how Priority and Severity of the bug given.
Some of the above points taken from this article
Many organizations mandate that bugs of certain severity should be at least certain priority. Example: Crashes must be P1; Data loss must be P1, etc. A severe bug that crashes the system only once and not always reproducible will not be P1, where as an error condition that results re-entry a portion of input for every user will be P1
Microsoft uses a four-point scale to describe severity of bugs and three-point scale for Priority of the bug. They are as follows
1. Bug causes system crash or data loss.
2. Bug causes major functionality or other severe problems; product crashes in obscure cases.
3. Bug causes minor functionality problems, may affect "fit anf finish".
4. Bug contains typos, unclear wording or error messages in low visibility fields.
1. Must fix as soon as possible. Bug is blocking further progress in this area.
2. Should fix soon, before product release.
3. Fix if time; somewhat trivial. May be postponed.
Comments and your experience in giving Severity & Priority for bug are welcome.