Defect density and detection rate in Testing Fundamentals - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is defect density in software testing?

Defect density is the number of defects found in a software module divided by the size of that module, usually measured in lines of code or function points. It helps measure software quality.

beginner

How do you calculate detection rate in testing?

Detection rate is calculated by dividing the number of defects found during testing by the total number of defects (found plus those found later). It shows how effective testing is at finding bugs.

intermediate

Why is defect density useful for project managers?

Defect density helps project managers understand which parts of the software are more error-prone and may need more attention or testing effort.

intermediate

What does a high detection rate indicate about a testing process?

A high detection rate means the testing process is good at finding defects before the software is released, reducing the chance of bugs reaching users.

beginner

If a module has 10 defects and 2000 lines of code, what is its defect density?

Defect density = Number of defects / Size of module = 10 / 2000 = 0.005 defects per line of code.

What does defect density measure?

A Number of defects per size of software

B Number of test cases executed

C Time taken to fix defects

D Number of users reporting bugs

Defect density measures how many defects exist per unit size of software, showing quality.

Detection rate is best described as:

A Defects found during testing divided by total defects

B Total defects divided by defects found during testing

C Number of test cases passed

D Time spent testing

Detection rate shows how many defects testing found compared to all defects.

A low defect density means:

A Software has many defects

B Software has fewer defects per size

C Testing was not done

D Software is very large

Low defect density means fewer defects per unit size, indicating better quality.

If detection rate is 100%, it means:

A Defects were found after release

B No defects were found

C All defects were found during testing

D Testing was skipped

100% detection rate means testing found every defect before release.

Which metric helps decide where to focus testing effort?

A Code coverage

B Detection rate

C Test case count

D Defect density

Defect density shows which parts have more defects and need more testing.

Explain defect density and why it is important in software testing.

Think about defects per size of software and what it tells us.

Describe detection rate and how it helps improve the testing process.

Consider how many defects testing finds compared to total defects.