Requirements Traceability

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Requirements Traceability
1.4.2001 Virve Leino QURE Project Software
Business and Engineering Institute Helsinki
University of Technology
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Contents

• Definition of requirements traceability
• Benefits of requirements traceability
• Factors affecting the need for traceability
• Traceability classes and relation types
• Techniques to document traceability
• Tools to document traceability
• Tasks to implement traceability
• Lessons learned in QURE -project

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Requirements traceability

• A requirement is traceable if you can discover
• who suggested the requirement,
• why the requirement exists,
• what requirements are related to it and
• how it relates to other information such as
  systems design, implementation and documentation.

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Benefits of Requirements Traceability

• Traceability helps in
• Requirements change management
• Validation and reuse of requirements
• Understanding how and why the system meets the
  needs of the stakeholders

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Factors affecting the need for traceability

• Type of the system
• Estimated system lifetime
• Number of requirements
• Size of the project team
• Level of organizational maturity
• Specific customer requirements

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Traceability classes 1/2Pre- and
post-traceability
Pre-traceability
Post-traceability
Origins of requirements
System process artifacts
Requirements
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Traceability classes 2/2 Forward and backward
traceability
Forward traceability
Origins of requirements
System process artifacts
Requirements
Backward traceability
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Traceability relation types
Rationales
1) requirement-source 4) requirement-requirement
2) requirement-rationale 5)
requirement-component 3) requirement-people 6)
requirement-verification
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Techniques to Document Traceability Information
1/3

• 1. Identifiers
• 2. Attributes
• 3. List
• 4. Table
• example of each technique follow...

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Techniques to document 2/3
1. Requirement-requirement information documented
using requirements identifiers
2. Requirement-source and requirement-verification
documented using requirements attributes
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Techniques to document 3/3
3. Requirement-component information documented
using list
4. Requirement-component information documented
using table
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Tools to Document Traceability Information

• General purpose tools (eg. spreadsheet programs,
  word processors, hypertext editors)
• suitable for small and short term projects
• not sufficient for extensive requirements tracing
  purposes
• Requirements management tools
• suitable for projects producing large and complex
  systems
• require investments (eg. licences, training
  end-users, system maintenance, consultation)

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Tasks to Implement Traceability

• Analyze the companys need for traceability
• Define which traceability relations should be
  documented
• Select techniques and tools to be used
• Choose when, by whom and to where information
  should be documented
• Ensure that practices are taken into use

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Lessons Learned in QURE -project

• Post-traceability
• many prerequisites
• clearly stated requirements, components and
  verificatíon-cases
• tool support is often needed to document it

• Pre-traceability
• first traceability that companies could benefit
  from
• easy to document (compared post-traceability)
• tool support is not needed