Overview
Let’s understand the Defect leakage software testing metric in this tutorial. It occurs when software bugs escape the testing process and manifest themselves in the live or operational environment.
Defect Leakage
Defect leakage is a metric used to measure the percentage of defects that were not detected during the development and testing phases and have subsequently made their way into the operational production environment or have been reported by customers after the software is released.
Defect Leakage Formula
The formula for calculating the defect leakage rate is as follows:
The total number of defects are the bugs identified in the SDLC phases like Development, Testing, etc before the product is released to the production environment.
This is a metric used to identify the efficiency of the QA team. It shows how many defects are missed by the testing/QA team during the testing phase.
Example
Let’s understand the concept using an example. Suppose a software project goes through the following scenario:
The development team works on implementing the requirements and fixing the identified defects. During this phase, 10 bugs were identified. The testing team conducts various tests, including functional, usability, and security testing. They identified and logged 60 bugs. After the software was released and being used by customers, they reported 15 defects.
To calculate the defect leakage rate, we will use the formula mentioned earlier.
Count the number of defects that have been reported by end users or defects discovered in the production environment after the software has been released. This is the Number of Defects Reported in the Production environment.
Number of Defects Found in Production = 15
Count the total number of defects that were identified during the entire development, testing, and other SDLC phases. This includes defects found during development, testing, and other quality control activities.
Total Number of Defects =10 + 60 = 70 bugs
Calculate the ratio and multiply the result by 100 to express the defect leakage rate as a percentage.
Defect Leakage Rate (%) = (15/70) * 100
= 21.42 %
The defect leakage rate for the project is approximately 21.42%.
This means that 21.42% of the total defects in the project were not caught during testing and were discovered by customers after the software was released to the production environment.
A higher defect leakage rate indicates that more defects are escaping into the production environment, suggesting that the testing and quality control processes may need improvement.
On the other hand, a lower defect leakage rate indicates that the testing processes are effective in catching and preventing defects from reaching the production environment.
This testing metric helps in assessing the effectiveness of the testing and QA processes. To mitigate defect leakage, software development teams often employ various testing strategies, such as unit testing, integration testing, system testing, and user acceptance testing. Additionally, continuous integration and continuous deployment (CI/CD) practices can help catch defects early in the development pipeline.
When defects do escape into the production environment, it can result in customer dissatisfaction, increased support costs, and potentially harm to the organization’s reputation. Therefore, organizations aim to minimize defect leakage through rigorous testing, quality assurance processes, and a focus on identifying and addressing defects as early as possible in the software development lifecycle.