Bug Severity and Bug Priority

Posted: September 3, 2012 in Testing Basics
Tags: , , , , ,

Bug severity describes how much damage a bug is doing. “Severity” is associated with standards.Severity would remain Constant.

Bug priority describes how important it is to fix that bug. Priority” is associated with scheduling.Priority would Change according to the situations.


Low priority High Severity:
If the application crashes after using it 100 times, it has high severity but low priority.

Any calculation error in Monthly/Quarterly/yearly generated report is High Severity and Low priority because this bug can fix in next release.

High Priority Low Severity:
If there is a spelling mistake in the home page, it is high priority but low severity.

Logo is missed or changed on web site is Low Severity and High priority bug because this bug needs to fix immediately.

A sample guideline for assignment of Priority Levels during the product test phase includes:

  1. Critical / Show Stopper: An item that prevents further testing of the product or function under test can be classified as Critical Bug. No workaround is possible for such bugs. Examples of this include a missing menu option or security permission required to access a function under test.
  2. Major / High: Defect that does not function as expected/designed or cause other functionality to fail to meet requirements can be classified as Major Bug. The workaround can be provided for such bugs. Examples of this include inaccurate calculations; the wrong field being updated, etc.
  3. Average / Medium: The defects which do not conform to standards and conventions can be classified as Medium Bugs. Easy workarounds exists to achieve functionality objectives. Examples include matching visual and text links which lead to different end points.
  4. Minor / Low: Minor priority is most often used for cosmetic issues that don’t inhibit the functionality or main purpose of the project, such as correction of typos in code comments or whitespace issues.

How to determine bug severity:

Blocker:  Application or major section freezes, crashes, or fails to start. Data is corrupted.

Critical:  Key feature does not work, cannot be used, or returns incorrect results.

Major: Key feature is difficult to use or looks terrible. A secondary feature does not work, cannot be used, or returns incorrect results.

Normal:  Secondary feature is difficult to use or looks terrible.

Minor: feature does not work, cannot be used, or returns incorrect results Minor Secondary feature has a cosmetic issue. Minor feature is difficult to use or looks bad.

Trivial:  Minor glitches in images, not so obvious spell mistakes, etc.

Enhancement:  Improvement to product features due to bad usability or based on feedback from users. This is not part of product requirements / design originally.

  1. Nikhil says:

    Thanks for clearing the doubts… 😀

    • geetha says:

      severity:Means Impact of bug on application.
      Levels of severity:
      Blocker:Example :Click on login page,it is showing blank this is a blocker bug.
      critical: example :login to page and send a mail,you will get confirmation message(successfully sent),but it is not received by user B this is example for critical.
      Priority :Means which bug to be fixed first.

  2. chintu says:

    nice answers …thank you

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