Difference between Severity and Priority of the bug

Severity of the bug

Severity of the bug means how severe impact this bug has on the application? how critical this bug is in terms of the usage of the application? how severely this bug is affecting any of the features of the application?

Priority of the bug

It means how urgently this bug needs to be fixed by the development team. It could be possible that the bug is not that severe in terms of using the application but it needs to be fixed urgently. On the other hand it is also possible that the bug is really severe but the fixing for the same could be delayed.

Both Severity and Priority of the bug could be classified as:

1. Critical

2. Major

3. Minor

4. Trivial

Example of a high severity and high priority bug

User is unable to log into the application. This bug is severe because user is unable to perform any task on the application as he is not able to log into the application. Also, this bug has high priority as it is affecting the business seriously and needs to be fixed urgently.

Example of a high severity and low priority bug

Suppose there is a page in the application that is not commonly accessed by the user and the link to that page is broken i.e. whenever user clicks on the link he gets the error message instead of the page getting loaded properly. Then this bug has high severity as user is unable to access a major functionality. But this bug is low priority i.e. the fixing for this bug could be delayed because this page in uncommon among the users of the application so this bug is affecting just a small fraction of people who use that feature of the application.

Example of a low severity and high priority bug

Let’s assume that the company name is misspelled on the home page of the application then although this bug is just a cosmetic bug not that critical one but it needs to be fixed urgently as the company’s reputation is at stake in this case. This bug which is just a spelling mistake and not affecting users to access any feature of the application needs to be fixed urgently as it is nothing else but the company name on the home page of the application that is misspelled. Another example could be the wrong logo of the company on every page, again this is a low severity but the high priority bug.

Example of a low severity and low priority bug

Suppose the Color combination on any page is not proper then this bug is not severe and also could be delayed for fixing as it is not affecting the business that much.

So, once the tester logs the bug into the bug tracking tool developers decide which bug needs to be fixed earlier than other bugs depending on the severity and priority of the bug as already discussed in previous sections.