Defect Severity classifies the software bug which specifies the level of negative effect on the software functionality or quality. The severity is a rule set by the tester when he creates a bug. Different companies uses different bug tracking tools, but below are the general severity levels:

Defect Severity Classification:

Below is the Defect Severity Classification:

1. Critical: When the bug hits the critical functionality or critical data. It doesn't have any solution to proceed.

Example: If the installation is not successful then its a critical bug.

2. Major: When the bug hits the major functionality or major data. It has a solution to proceed but is not obvious and is difficult.

Example: A feature is not working from one module but the task is able to do if 10 complicated indirect steps are followed in other modules.

3. Minor: When the bug hits the minor functionality or non-critical data. It has an easy solution to proceed.

Example: A minor bug that is not working in one module but it is easily able to do from other module.

4. Trivial: When the bug does not hit any functionality or data. It does not even need any solution to proceed.

Example: Slight design variation, spelling/grammatical errors.

Severity is also denoted as:

S1 = Critical
S2 = Major
S3 = Minor
S4 = Trivial

Caution:

Bug Severity is also one of the reason of conflict between Testers and Developers. Because sometimes testers sets the bug severity as critical or major but developers are disagree with this. They may believed that the bug is of Minor.