Bug Severity vs Priority in Testing

‘Bugs’ is the definitive buzzword in the Software Testing landscape. With every release cycle, the whole idea behind testing is to find bugs in software before it reaches the users. Several types of testing, test reporting, and bug tracking are done to ensure that the bugs found during software development are rectified to deliver high-quality, bug-free applications.

Bug Severity and Bug Priority are commonly used in finding and rectifying bugs. However, they are often used interchangeably, which is incorrect.

Severity and priority in software testing are two important concepts used to prioritize and classify issues found during testing.

• Severity refers to the impact of a defect on the functionality or the end-user experience. It measures how severe the issue is and how critical it is to fix it. The severity of a defect can be classified into levels such as high, medium, or low.
• Priority refers to the urgency with which a defect needs to be fixed. It measures how quickly the issue should be resolved based on the business impact or the project timeline. The defect priority of a defect can also be classified into different levels such as high, medium, or low.

This article discusses each of them in detail and explains the difference using examples.

What is Bug Severity?

Bug severity measures the impact a defect (or bug) can have on the development or functioning of an application feature when it is being used. It depends on the effect of the bug on the system. Depending on how much of a threat the bug can pose to the software, bug severity can be divided into multiple levels:

• Low: Bug won’t result in any noticeable breakdown of the system
• Minor: Results in some unexpected or undesired behavior, but not enough to disrupt system function
• Major: Bug capable of collapsing large parts of the system
• Critical: Bug capable of triggering complete system shutdown

Usually, QA engineers are the ones to determine the level of bug severity.

How to determine Bug Severity?

1. Identify how frequently the bug can occur. Even if the bug is minor, it can be problematic if it frequently occurs in the code. In this case, the minor defect can majorly disrupt the end-user experience.
2. Once the defect has been isolated and identified, it can be examined to evaluate its severity.

What is Bug Priority?

Bug priority refers to how urgently a bug must be fixed and eliminated from the website or app. It measures how the bug should be prioritized in the debugging hierarchy. Correctly assigning bug priority and setting up a bug triage process is integral to successfully planning a software development life cycle.

Levels of bug priority:

• Low: Bug can be fixed at a later date. Other, more severe bugs take priority
• Medium: Bug can be fixed in the ordinary course of development and testing.
• High: Bug must be resolved as soon as it affects the system adversely and renders it unusable until resolved.

Testers can determine bug priority with the same steps described earlier to determine bug severity.

Bug Severity vs Priority: Key Differences

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High Severity and Low Priority Example

A website renders multiple flaws in some legacy browsers. The logo does not load, the text scrambles, and the images are too pixelated. Since this is a disruption to product functionality as well as user experience, bug severity is high. However, since the problem only occurs with legacy browsers, it won’t affect many users. Hence, bug priority is low.

High Severity and High Priority Example

A website is being tested on Chrome and works perfectly. But when switched to Edge, the pricing page shows major flaws. Buy buttons for purchasing plans have disappeared, and so has the text that outlines the prices and corresponding features included in each plan. In this case, anyone using Firefox cannot buy or even know the product’s details.

Hence cross browser compatibility beyond Chrome is essential and should be considered during software testing.

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Since key functions are being adversely affected, bug severity is high. In such cases, the broken functions block a key phase of the user journey (actually buying the product). Hence, bug priority is high.

Low Severity and High Priority Example

While testing the functionality of a website, it is seen that buttons are slightly out of place when the site is run on Chrome. They can still be clicked easily and do what they are meant to. This means that functionality is not affected; hence bug severity is low. However, since out-of-place buttons don’t exactly make for a pleasurable visual representation and badly designed websites actively turn off users, bug priority is high. The issue needs to be fixed as fast as possible.

Low Severity and Low Priority Example

Among many severity and priority real-time examples, one of the most common issues software companies face is a lack of uniformity in their text.

While testing the website, some of the text is found to have typos, and the font and color do not match the color and font of the website’s primary design. Now, this is a bug for sure, but it is certainly not a real problem in functionality. Hence, bug severity is low. Similarly, it does not need to be fixed immediately, so bug priority is low.

Debugging using Real Devices 

Now, it is impossible to assign bug priority and severity without knowing the exact nature of the bug. Also, it’s essential to know how frequently a bug occurs and how it affects the software. However, no matter which level of Bug Severity or Bug Priority your bug has, detecting and debugging it using real devices is the most effective way.

• The best way to detect all bugs is to run the software through BrowserStack Real Device Cloud.
• When it comes to a website, ensure it is under the purview of manual and automation testing.
• Automation Selenium testing should supplement manual tests so that testers do not miss any bugs in the Quality Assurance process.
• Moreover, cross browser testing and cross platform testing should be considered while detecting and debugging bugs for a seamless and consistent user experience.
• Access real devices for mobile app testing and automated app testing. Simply upload the app to the required device-OS combination and check how it functions in the real world.
• With BrowserStack’s latest offering on Test Observability, teams can debug with surgical precision and fix faster with Smart Failure Analysis, which learns from your testing and identifies the causes of test failures. Detect and fix flaky tests with intelligent suggestions or mute them to avoid false alarms.

Debug on BrowserStack

Testers can find the number of bugs, their nature, and how often they occur by testing in real user conditions. Then, they can accurately assign bug severity and priority in testing. This, in turn, helps to run debugging activities in the correct order so that the software can provide the best possible service to its users at any given time.