A defect is the representation of an misunderstanding of specification or syntax error, where representation is the mode of expression. Defect severity is the classification of a defect based on its level of destructive impact on the requirements specification of the Software.
Defect Severity :
Following are some of the commonly used defect severity classes in the software development:
- Critical –
A defect that completely obstructs the execution of a core functionality/feature of the software is classified a critical defect. This defect affects the critical functionalities and data and makes the testing of the software difficult. It is represented by S1.
Example: We have a login interface for a mobile application. When a user taps on forgot password, the user is asked to enter the OTP which he/she receives on his registered mobile number or email. Upon entering the OTP (correct/incorrect), a loader is displayed and continues indefinitely. Since, the user is not able to login to access the functionalities of the mobile application, it is a critical defect.
- Major –
A defect that makes a major functionality/feature to behave grossly away from what is specified in the requirements specification of the software is classified a major defect. This defect affects the major functionalities and data. It is represented by S2.
Example: We have a login interface for a mobile application and the system is allowing the access to the platform under the entered username without validating the password for its respective username. As a result, an unauthorised user can access the account leading to a major defect causing theft of personal data and criminal activity.
- Minor –
A defect which occurs when a functionality/feature does not behave as intended or exhibits some unnatural behavior, however the functionality/feature as a whole is not much impacted is classified a minor defect. This minimally affects the functionalities and data. It is represented by S3.
Example: We have a login interface for a mobile application. The user enters his username and password, and after validation the user successfully logins to his/her account but is displayed “Login Unsuccessful Please try again later” prompt window instead. This is a minor defect as he is just shown a wrong prompt window.
- Trivial –
Any cosmetic defects such as misplaced images, spelling mistakes or alignment issues or font casing is classified a trivial defect. This defect does not affect functionalities and data. It is represented by S4.
Example: We have a login interface for a mobile application and the login credentials have a incorrect order that is the password field is placed above the username field.