Difference Between Bug and Defect

The main difference between bug and defect is that the bug is an outcome of a coding fault while the defect is a variation from the original business requirement.  

Software testing is the process of identifying the accuracy, completeness, and quality of the developed software. It involves finding failures that should be corrected before the product is released to end users. Testing helps to produce a quality software as the final product. During the development process, the software can be affected by a bug or a defect. A bug is a mistake in programming whereas a defect is a deviation from the original business requirement. However, terms bug and defect are often used interchangeability.

Key Areas Covered

1. What is a Bug
     – Definition, Functionality
2. What is a Defect
     – Definition, Functionality
3. Difference Between Bug and Defect
     – Comparison of Key Differences

Key Terms

Bug, Defect, Software Testing

Difference Between Bug and Defect - Comparison Summary

What is a Bug

A bug is a consequence of a mistake or error in the program source code.  A compiler can also cause bugs, which result in producing incorrect code. A bug can even result in a crash or freeze the computer. Some bugs can give access to the user’s personal details to unauthorized parties.

Sometimes, a bug can cause disasters. For example, the Threac-25 radiation therapy machine was the reason for the death of patients in 1980s. Furthermore, the European Space Agency’s prototype Ariane 5 rocket, which was destroyed less than a minute after launching, occurred due to a bug in the on-board guidance computer program. 

There are various methodologies to reduce bug count. There are various programming styles and defensive programming that can easily spot bugs. Programming languages consist of features to prevent bugs. Some of them are restricted namespaces, modular programming etc. Moreover, there are tools for analyzing code that helps the developers to inspect the program beyond the compiler’s capability to detect a bug.

Difference Between Bug and Defect

The process of fixing bugs is called debugging. Special programs called debuggers help the programmers to find bugs by executing the code line by line. It allows monitoring of the variable values and other features to observe the program behavior.

What is a Defect

A defect is a deviation from the original business requirement. During the testing phase, the software tester executes test cases. There can be test results that are diffident from the expected results. This variation of the test results is known as a software defect. The defect report includes the following information.

Main Difference -  Bug vs Defect

Following a defect management process is an effective method to manage defects. First, in the discovery phase, defects are discovered as much as possible. The second phase is the categorization. It includes prioritizing the defects according to high priority and minimum priority. Thus, it helps to get an understanding of what defects should be fixed immediately.

The third phase is resolution. It is in this stage that steps are taken to fix the defect. The fourth phase is verification. It ensures that the defects are actually resolved. The fifth phase, which is closure, changes the status of a detect to “closed”. If not, steps are taken to check the defect again. The final phase is reporting, which includes reporting the defect to get feedback from the managerial level.

Difference Between Bug and Defect

Definition

A bug is a failure in a computer program that causes it to produce an incorrect or unexpected result or to behave in an unintended manner whereas, a defect is a failure in a computer program that has a variation between the actual result and the expected result.

Basis

Furthermore, a bug is a coding fault while a defect is a deviation from the original business requirement.

Conclusion

The difference between bug and defect is that the bug is an outcome of a coding fault while the defect is a variation from the original business requirement. Even though a bug and a defect have a difference, they are often used interchangeably.

Reference:

1. “Software Bug.” Wikipedia, Wikimedia Foundation, 12 Aug. 2018, Available here.
2. “What Is Software Bug? Learn Defect Management Process.” Meet Guru99 – Free Training Tutorials & Video for IT Courses, Available here.

Image Courtesy:

1. “762486” (CC0) via Pixabay

About the Author: Lithmee

Lithmee holds a Bachelor of Science degree in Computer Systems Engineering and is reading for her Master’s degree in Computer Science. She is passionate about sharing her knowldge in the areas of programming, data science, and computer systems.

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