Requirement Traceability Matrix (RTM)

Requirements tracing is the process of documenting the links between the user requirements for the system you're building and the work products developed to implement and verify those requirements. These work products include Software requirements, design specifications, Software code, test plans and other artifacts of the systems development process. Requirements tracing helps the project team to understand which parts of the design and code implement the user's requirements, and which tests are necessary to verify that the user's requirements have been implemented correctly.

Requirements Traceability Matrix Document is the output of Requirements Management phase of SDLC.

The Requirements Traceability Matrix (RTM) captures the complete user and system requirements for the system, or a portion of the system. The RTM captures all requirements and their traceability in a single document, and is a mandatory deliverable at the conclusion of the lifecycle.

The RTM is used to record the relationship of the requirements to the design, development, testing and release of the software as the requirements are allocated to a specific release of the software. Changes to the requirements are also recorded and tracked in the RTM. The RTM is maintained throughout the lifecycle of the release, and is reviewed and baselined at the end of the release.
It is very useful document to track Time, Change Management and Risk Management in the Software Development.
Here I am providing the sample template of Requirement Traceability Matrix, which gives detailed idea of the importance of RTM in SDLC.

The RTM Template shows the Mapping between the actual Requirement and User Requirement/System Requirement.
Any changes that happens after the system has been built we can trace the impact of the change on the Application through RTM Matrix. This is also the mapping between actual Requirement and Design Specification. This helps us in tracing the changes that may happen with respect to the Design Document during the Development process of the application. Here we will give specific Document unique ID, which is associated with that particular requirement to easily trace that particular document.

In any case, if you want to change the Requirement in future then you can use the RTM to make the respective changes and you can easily judge how many associated test scripts will be changing.

Requirements Traceability Matrix Template Instructions:

Introduction
This document presents the requirements traceability matrix (RTM) for the Project Name [workspace/workgroup] and provides traceability between the [workspace/workgroup] approved requirements, design specifications, and test scripts.
The table below displays the RTM for the requirements that were approved for inclusion in [Application Name/Version]. The following information is provided for each requirement:
1. Requirement ID
2. Risks
3. Requirement Type (User or System)
4. Requirement Description
5. Trace to User Requirement/Trace From System Requirement
6. Trace to Design Specification
7. UT * Unit Test Cases
8. IT * Integration Test Cases
9. ST * System Test Cases
10. UAT * User Acceptance Test Cases
11. Trace to Test Script

The following is the sample Template of Requirements Traceability Matrix.

Disadvantages of not using Traceability Matrix
What happens if the Traceability factor is not considered while developing the software?
a) The system that is built may not have the necessary functionality to meet the customers and users needs and expectations
b) If there are modifications in the design specifications, there is no means of tracking the changes
c) If there is no mapping of test cases to the requirements, it may result in missing a major defect in the system
d) The completed system may have �Extra� functionality that may have not been specified in the design specification , resulting in wastage of manpower, time and effort.
e) If the code component that constitutes the customer�s high priority requirements is not known, then the areas that need to be worked first may not be known thereby decreasing the chances of shipping a useful product on schedule
f) A seemingly simple request might involve changes to several parts of the system and if proper Traceability process is not followed, the evaluation of the work that may be needed to satisfy the request may not be correctly evaluated

Where can a Traceability Matrix be used?
Is the Traceability Matrix applicable only for big projects?
The Traceability Matrix is an essential part of any Software development process, and hence irrespective of the size of the project, whenever there is a requirement to build a Software this concept comes into focus.
The biggest advantage of Traceability Matrix is backward and forward traceability. (i.e) At any point of time in the development life cycle the status of the project and the modules that have been tested could be easily determined thereby reducing the possibility of speculations about the status of the project.

Developing a Traceability Matrix
How is the Traceability Matrix developed?

In the diagram, based on the requirements the design is carried out and based on the design, the codes are developed. Finally, based on these the tests are created. At any point of time , there is always the provision for checking which test case was developed for which design and for which requirement that design was carried out. Such a kind of Traceability in the form of a matrix is the Traceability Matrix.

In the design document, if there is a Design description A, which can be traced back to the Requirement Specification A, implying that the design A takes care of Requirement A. Similarly in the test plan, Test Case A takes care of testing the Design A, which in turn takes care of Requirement A and so on.

There has to be references from Design document back to Requirement document, from Test plan back to Design document and so on.

Usually Unit test cases will have Traceability to Design Specification and System test cases /Acceptance Test cases will have Traceability to Requirement Specification. This helps to ensure that no requirement is left uncovered (either un-designed / un-tested).

Requirements Traceability enhances project control and quality. It is a process of documenting the links between user requirements for a system and the work products developed to implement and verify those requirements. It is a technique to support an objective of requirements management, to make certain that the application will meet end-users needs.

Traceability Matrix in testing
Where exactly does the Traceability Matrix gets involved in the broader picture of Testing?
The Traceability Matrix is created even before any test cases are written, because it is a complete list indicating what has to be tested. Sometimes there is one test case for each requirement or several requirements can be validated by one test scenario. This purely depends on the kind of application that is available for testing.
Creating a Traceability Matrix
Traceability Matrix gives a cross-reference between a test case document and the Functional/design specification document. This document helps to identify, if the Test case document contains tests for all the identified unit functions from the design specification. From this matrix we can collect the percentage of test coverage taking into account the percentage of functionalities to the total tested and not tested.

According to the above table, the requirement specifications are clearly spelt out in the requirement column. The functional specification notified as BRD section 6.5.8 tells about the requirement that has been specified in the Requirement document (i.e it tells about the requirement to which a test case is designed). With the help of the Design Specification, it is possible to drill down to the level of identifying the Low Level Design for the Requirement specified.
Based on the requirements, code is developed. At any point of time, the program corresponding to a particular requirement could be easily traced back. The test cases corresponding to the requirements are available in the Test Case column.

Bidirectional traceability is the ability to trace both forward and backward (i.e., from requirements to end products and from end product back to requirements).

It means tracing the code from requirements and vice-versa throughout a Software Development Life Cycle (SDLC). When you are in the course of your project, your fundamental aim would be to ensure that each and every requirement is translated into code. Tracing right from the requirements through the architecture and design, to the code, to ensure that the objectives or more precisely requirements have been met is referred to as the process of establishing Forward Traceability.

When you think about maintenance, invariably, due to economic and technical considerations your client will come back to you. At this juncture, you will debug; or rather you will hunt for various types of bugs. You should be in a position to go back to the requirements of corresponding code or architectural components. To achieve this you ought to trace back your code and design to their corresponding requirements. This process is called Backward Traceability.