Defect Life Cycle Explained for Beginners

If you are starting your journey in software testing, you will often hear about the Defect Life Cycle (also called the Bug Life Cycle). This is the process a defect goes through from the moment it is found until it is fixed, verified, and closed.

Knowing this cycle is important because it helps you understand how bugs are tracked, communicated, and resolved in a professional QA environment.

What is a Defect Life Cycle

The defect life cycle is a series of stages that a defect passes through during its lifetime. Each stage represents the current state of the defect in the workflow.

A clear life cycle ensures that everyone on the team knows the status of a bug, who is responsible for it, and what the next step is.

Stages of the Defect Life Cycle

While the exact names of the stages can vary between companies or bug tracking tools, the typical flow looks like this:

1. New

The tester finds a defect and reports it in the bug tracking system. At this point, the bug is awaiting review.

Tip: A good bug report increases the chance of quick triage. See How to Write Bug Reports That Don’t Suck for tips.

2. Assigned

The defect is assigned to a developer or a team responsible for fixing it. This may be done by a project manager, QA lead, or automatically by the system.

3. Open

The developer starts working on the defect. They analyze it, identify the root cause, and make changes to fix it.

4. Fixed

The developer has implemented the fix and marked the defect as resolved. The fix is now ready for verification by QA.

5. Retest

The tester verifies if the defect has truly been fixed by executing the relevant test cases.

6. Verified

If the defect no longer occurs and the fix works as expected, the tester marks it as verified.

7. Closed

The tester closes the defect. This means it has been fixed, tested, and confirmed as resolved.

Possible Alternate States

In addition to the main stages, you might also encounter these states:

• Rejected: The reported issue is not considered a defect, often due to misunderstanding or intended behavior.
• Deferred: The defect is acknowledged but will be fixed in a future release due to low priority.
• Duplicate: The defect is already reported elsewhere in the system.
• Cannot Reproduce: The tester or developer cannot replicate the defect with the given steps.

Why Understanding the Defect Life Cycle Matters

• Improves communication between QA, development, and management
• Helps track the progress of bug fixes
• Ensures that no defect is forgotten or left unresolved
• Creates accountability for each step in the process

Final Thoughts

Mastering the defect life cycle will make you a more effective tester and a better communicator within your team. It is one of the core concepts in QA, and understanding it early will help you work more confidently in any testing role.

Related reading: You can improve your defect reporting skills by reading How to Write Bug Reports That Don’t Suck, learn ways to find more bugs with Exploratory Testing for Beginners, and focus your effort when time is short with How to Prioritize Test Cases When You Have Limited Time.