difference between Severity and Priority?

There are two key things in defects of the software testing. They are:

1)     Severity

2)     Priority

1)  Severity:

It is the extent to which the defect can affect the software. In other words it defines the impact that a given defect has on the system. For example: If an application or web page crashes when a remote link is clicked, in this case clicking the remote link by an user is rare but the impact of  application crashing is severe. So the severity is high but priority is low.

Severity can be of following types:

  • Critical: The defect that results in the termination of the complete system or one or more component of the system and causes extensive corruption of the data. The failed function is unusable and there is no acceptable alternative method to achieve the required results then the severity will be stated as critical.
  • Major: The defect that results in the termination of the complete system or one or more component of the system and causes extensive corruption of the data. The failed function is unusable but there exists an acceptable alternative method to achieve the required results then the severity will be stated as major.
  • Moderate: The defect that does not result in the termination, but causes the system to produce incorrect, incomplete or inconsistent results then the severity will be stated as moderate.
  • Minor: The defect that does not result in the termination and does not damage the usability of the system and the desired results can be easily obtained by working around the defects then the severity is stated as minor.
  • Cosmetic: The defect that is related to the enhancement of the system where the changes are related to the look and field of the application then the severity is stated as cosmetic.

2)  Priority:

Priority defines the order in which we should resolve a defect. Should   we fix it now, or can it wait? This priority status is set by the tester to the developer mentioning the time frame to fix the defect. If high priority is mentioned then the developer has to fix it at the earliest. The priority status is set based on the customer requirements. For example: If the company name is misspelled in the home page of the website, then the priority is high and severity is low to fix it.

Priority can be of following types:

  • Low: The defect is an irritant which should be repaired, but repair can be deferred until after more serious defect have been fixed.
  • Medium: The defect should be resolved in the normal course of development activities. It can wait until a new build or version is created.
  • High: The defect must be resolved as soon as possible because the defect is affecting the application or the product severely. The system cannot be used until the  repair has been done.