Classification of Software Errors

Once you have learned the basics of software error classification, you understand that responsible software development teams need to delegate the bug fixing. Plus, you can make it easier to prioritize any issues. This results in faster correction and also improves the overall efficiency of testing and development processes, as well as minimizes the inconveniences for the actual users.

There are three software error classification types: 

• By severity 
• By priority
• By nature

Although the classifiers for the first two are in the default error tracking systems, I would recommend setting up the classifier to separate errors by nature because it makes it much easier to distribute bug fixing tasks among responsible development teams.

Software Error Classification Types

Software Errors by Nature

By their nature, there are such software glitches.

Functional Errors

If the behavior of the software does not meet the functional requirements, then this type of error is detected. They can be found through functional testing. For example, in a past test project that ran on an e-commerce website search engine, we found a functional bug. When the user entered the product ID, it did not show any results, even though the search can be done by both the product name and the ID.

Performance Issues

Performance problems are primarily related to the response time and resource consumption of the software and its speed and stability. They are discovered during performance testing. When the system response time is X times longer than specified in the requirements, this is an issue for investigation and correction.

Usability Errors

The application becomes inconvenient to use because of the lack of usability, making it difficult for the user to work. Examples of usability bugs include a content layout that is difficult to scan or move or a very difficult and time-consuming registration process. To identify such issues, QA engineers and business analysts validate the software against the Web Content Accessibility Guidelines (WCAG) usability requirements during usability testing.

Compatibility Bugs

We do compatibility testing to identify compatibility malfunction. After all, an application with compatibility errors does not integrate properly with the third-party software, or does not work in certain network configurations, and does not show stable performance on certain hardware, operating systems, browsers, and particular devices. For example, when we tested the mobile app for assessing insurance claims by car, it was found that it did not work under the requirements of a particular mobile platform. These bugs are related to changes in font size, content alignment, and scroll bar.

Security Vulnerabilities

Security vulnerabilities are weak points that allow for a potential security attack. The most common security flaws in projects for which we conduct security testing are encryption bugs, XSS vulnerability, SQL injection vulnerabilities, weak authentication, buffer overflows, and logical errors in role-based access.

Software Errors by Severity

Software error classification by severity is based on the technical impact the bugs/errors have on the system. While testing the client’s software, we can distinguish the following levels of severity:

Critical Errors

They always block the entire system's operation, and in this case, testing cannot be carried out. For example, when a critical bug occurs, a message sent by the application is constantly returned, that an error prevents us from logging in.

Issues of High Severity

They affect the main functions of the application, without which its operation is impossible, and the application behaves completely differently from what is specified in its requirements.

Issues of Moderate Severity

They are detected when one of the functions does not behave as specified in the requirements. An example of such a bug is a broken link in the privacy policy section.

Errors or Bugs of Low Importance

An example can be the bug with the user interface. These bugs have no significant influence on the functionality, for example, a different color or size of the button, or ugly looking dashboard, squeezed on the tablet, while nice looking on the mobile screen.

The Necessity of Classifying Bugs

Considering that the severity of the error and the priority levels affect the assessment of the effectiveness of the development process and can affect the fees and penalties in case of outsourced development, it is extremely important to define criteria for assessing the severity of the error and set the priority for its correction.