Difference Between Severity and Priority in Testing

What is Severity in Testing?

In software testing, severity is a measure of the impact or severity of a defect or problem found in the software. It indicates how many failures can affect the functionality of the system or its ability to meet requirements.

The severity of a failure is usually determined by factors such as the nature of the failure, its impact on the system, the criticality of the functionality of the failure, and the extent of the damage caused by the failure. Severities are usually classified into four or five categories, such as critical, major, minor, and cosmetic.

Types of Severity

The severity of the error is usually classified into five levels, depending on how the problem affects the functionality of the system. Severity levels can vary depending on an organization's testing process, but the most commonly used categories are:

1. Critical : A critical failure is a problem that causes the system to crash, lose data, or significantly affect system performance. This can seriously affect system performance and requires immediate attention and resolution.
2. Major : A critical failure is a problem that affects the operation of the system but does not cause it to crash or cause data loss. This can cause false results, unexpected behaviour, or system instability. This type of failure must be repaired as soon as possible, but it is not as urgent as a critical failure.
3. Minor : A minor defect is a problem that does not affect the overall function of the system but may affect the user experience or cause inconvenience. It may contain typos, formatting issues, or minor user interface issues. These types of bugs may be fixed in the next version or iteration.
4. Cosmetic : A cosmetic defect is a problem that affects the appearance or user interface of the system but does not affect the operation of the system. This can include problems such as incorrect colour schemes, paragraph problems, or font problems. Cosmetic defects do not affect system performance or functionality and may be corrected in the next release.
5. Enhancements : Some organizations use an additional severity level called Enhancements, which indicates a request for new features or improvements to existing features. It does not contain bugs, but there is a request for additional features or changes to improve the functionality of the software.

What is Priority in Testing?

Priority refers to the importance or urgency of fixing a bug or problem found in the software. This helps prioritize defects and effectively allocate resources to resolve them.

The priority level of an error is usually determined based on the effect of the error on the user or system, the criticality of the functionality of the error, and the extent of the damage caused by the error. Priority levels are usually classified into four or five categories, such as high, medium, low and none.The priority of the bug is indicated by specifying the priority level in numerical or alphabetical order. This helps the development team prioritize which bugs to fix first based on their impact on the software and end users. Higher-priority bugs are given larger numbers or letters to indicate greater urgency.

Types of Priority

The priority of defects is usually classified into four or five levels based on the urgency of solving the problem. Priority levels can vary depending on an organization's testing process, but the most commonly used categories are:

1. High : A high-priority failure is a problem that requires immediate attention because it significantly affects system operation or poses a significant risk. This can lead to data loss, system crashes or security breaches. Major errors must be corrected as soon as possible.
2. Medium : A medium-priority failure is a problem that affects the operation of the system, but is not as urgent as a high-priority failure. This may cause incorrect results or affect the stability of the system, but it does not pose a serious risk. These types of bugs should be fixed in the next version or iteration.
3. Low: A low-priority failure is a problem that has little impact on system functionality or user experience. It may contain typographical errors, minor formatting problems or cosmetic defects. These types of bugs may be fixed in the next version or iteration.
4. None : A non-priority error is a problem that does not affect system functionality or user experience. This may include issues such as document errors, duplicate entries or trivial issues. These types of defects may not require action or may be repaired at the end of the project.

Key Difference Between Severity and Priority

The main difference between Severity and Priority lies in their focus and decision-making process. Severity is an objective measure that remains constant over time, assessing how severely a defect impacts functionality or standards. It is determined by the technical impact of the issue. On the other hand, Priority is a subjective measure that can change over time, reflecting how urgently a defect needs to be addressed. It is decided based on business value and scheduling considerations. While Severity is typically assessed by testing engineers, Priority is determined by product managers who prioritize defects based on their potential impact on the project’s overall goals. This distinction ensures that both technical and business aspects are considered in defect management.

Difference Between Severity and Priority

Defect Severity and Priority Examples

Here are some examples of how to classify the severity and priority of defects in software testing.

Example 1:

Error: Login page not loading.

Severity: High

Priority: High

Explanation: The bug prevents users from using the app, which is an important feature. Therefore, it must be fixed immediately to avoid any negative impact on users.

Example 2:

Error: The application font is incorrect.

Severity: Low

Priority: Low

Explanation. Although the bug does not affect the functionality of the app, it is still a visual problem that should be fixed. However, this is not a high priority because it does not significantly affect the user experience.

Example 3:

Bug: The application crashes when a user enters invalid data.

Severity: High

Priority: Medium

Explanation. The error affects the operation of the application and prevents users from taking necessary actions. However, this is not considered a priority because users may have workarounds and it will not affect a large number of users.

Example of defect Severity :

1. Critical: The software crashes or causes data loss, making it impossible to use.
2. Major: The function does not work as intended, affecting the basic functions of the software.
3. Minor: A cosmetic issue such as a misspelled word or an incorrect button that does not affect the functionality of the software.

Example of defect Priority :

1. High Priority: A critical issue that affects the core functionality of the software and must be resolved as soon as possible.
2. Medium priority: a major problem that affects the functionality of the software but has a solution or the problem does not affect most users.
3. Low Priority: A minor issue that has little or no impact on the functionality or user experience of the software.