What is the difference between bug priority and severity?

• Priority determines how quickly a defect should be fixed. It is determined by the product manager or business analyst and depends on the impact on the business.
• Severity defines the degree of impact of the defect on the functionality or performance of the system. It is determined by the QA engineer and depends on the technical aspect.

Examples of combinations:

Priority	Severity	Description
High	High	Critical bug blocking the main function.
High	Low	Minor visual error on the main page.
Low	High	Rare error causing system crash in exotic scenarios.
Low	Low	Typo in text that does not affect functionality.