What is a Traceability Matrix
From Requirements Management School
A traceability matrix allows bidirectional tracing of requirements. It can be used at varying stages during a software project to ensure nothing is missed.
With a traceability matrix - requirements can be traced back to their origin and also forward to the functionality produced. Other names for a traceability matrix are:
- Requirements trace matrix
- Traceability table, and
- Traceability matrices (Just the plural form)
Benefits of Traceability Matrix
The reasons for needing bidirectional traceability are many fold:
- As a tool to assist with the management of the scope of the project.
- As a tool to assist with the change control process.
- As a road map linking all the documentation for each requirement.
- As a verification and validation to full implementation of the SRS.
- It highlights whether or not all requirements have been met and whether or not there is any additional unauthorized functionality creeping in.
- Can be used as the foundation for test planning.
How to Create Traceability Matrix
Once the baseline has been set the traceability matrix is usually set up. There are various tools that can be used - requirements management tools; spreadsheets such as Microsoft Excel; and the table function in a word processor such as Microsoft Word. Spreadsheets and word processor documents are only a viable option for small projects as they soon become unwieldy.
For a fully comprehensive traceability matrix each requirement in the SRS will be correlated to:
- A use case/source
- The architectural/design document
- The SRS
- System components
- Software modules
- Test case
- Verification document
As you can see from the above list the data that needs to be gathered comes from many stakeholders. This means that a cross-functional effort will be needed in order to keep the data up to date. Best practice dictates that the requirements analyst set up the initial process populating the traceability matrix with the unique identifier for each requirement. Then as each stage in the development and testing phases is underway the relevant stakeholders update the remaining data.
Caveats
Often the use of a traceability matrix is a hard sell to many stakeholders because of the additional work involved in creating it.
However, it is fairly easy to make an argument for its implementation due to the reasons that we listed above. Furthermore, good requirements management tools can enable you to produce a traceability matrix rather quickly. An example of this is Accompa requirements management software, which is quite reasonably priced and enables you to create traceability matrix quickly - they have explained their traceability matrix feature here.
For projects of reasonable complexity, traceability matrices can be invaluable and are often worth the investment of time and resources.
