Overview
In this tutorial, we will learn about defect migration. Defect migration is the phenomenon where defects or bugs move from one stage of the software development process/testing phase to another or from one environment to another. This happens for various reasons, such as inadequate testing, incomplete bug fixes, differences in environments, etc.
Defect Migration
A Migrated Defect is defined as a defect that ideally should have been found in previous software testing phases.
Examples
Development to Testing
Defects can migrate from the development environment to the testing environment if the development team fails to identify and fix all issues before passing the code to the testing phase. This can happen due to oversight, lack of proper testing protocols, or miscommunication between development and testing teams.
Testing to Production
If defects are not identified and resolved during testing, they can migrate to the production environment when the software is deployed for end-users. This can lead to disruptions in service, user dissatisfaction, and potentially costly fixes.
Defect Migration Index
The Defect Migration Index (DMI) metric measures the defect migration from one phase to another.
DMI of Testing Phase T -> to Phase X =
Number of Migrated Defects from Phase X/ Number of Defects found in Testing Phase T
DMI accounts for the migrated defects to a testing phase. In an ideal environment, it should be zero. The key objective of the testing process is to stop the Defect Migration.
DMI measures the performance of the testing activity and serves as a metric showing the effectiveness of the testing in stopping the defect migration. Unlike Defect Removal Efficiency, this accounts for defects migrated from any Phase X to Testing Phase T. The DMI chart shows the DMI metric on the chart.