How Requirements Traceability Enhances Accuracy and Reduces Rework

The concept of "requirements traceability" is pretty self-explanatory, and, in the wake of increased supply chain disruption risk, more organizations are striving to improve the traceability of the electronic design processes. In the context of printed circuit board (PCB) design requirements, requirements traceability can provide unique benefits - minimizing the need to rework electronics and encouraging more input from sourcing teams to understand where faults lie.

Generally, an end product defect falls on the shoulders of its designers, but requirements management considers the vast number of people and variables in the supply chain to be just as important. However, to take full advantage of traceability, it is crucial to know what true traceability looks like, the capabilities of requirements traceability tools, and how to apply them to various electronic development contexts.

All project stakeholders can benefit from a clear method of design and parts verification. Requirements traceability can be a game-changer for determining the source of defects through the design itself, both from specific design features and by fact-checking supply chain elements to eliminate cases where production and distribution impact the function and delivery of new products.

What Is Requirements Traceability?

Requirements traceability is the process of documenting the lifecycle of a requirement. It traces forward from a requirement to its implementation and testing, ensuring it is built. It also traces backwards from the product to the requirement, ensuring every feature is justified and preventing unnecessary work. Bidirectional traceability indicates support for tracing requirements in both directions.

Forward Traceability

As an effective way of managing requirements throughout the product life cycle, forward traceability emphasizes design specification and material selection. It ensures each design step adheres to the initial requirements and drives all actions downstream. 

Further benefits: 

• Compliance with Industry Standards: When developing PCBs for highly regulated industries like aerospace, automotive, and medical technology, forward traceability gives designers the power to track compliance. Designers are able to provide proof of compliance to supply chain stakeholders. 
• Component Lifecycle Management: Forward thinking helps designers recognize when certain components near their end-of-life. This allows a more proactive means of managing parts obsolescence. 
• Supply Chain Optimization: Forward traceability in the event of inventory shortage allows companies to see the impact of a shortage on downstream delivery times. 

Backward Traceability

Backward requirements traceability allows teams to trace from design implementations, test results, or identified issues back to their originating requirements. This is essential for defect investigation and root cause analysis, enabling designers to determine whether problems stem from incorrect requirements, design decisions that didn't properly address requirements, or implementation gaps.

Further benefits:

• Requirements Verification: Teams can trace from specific design elements or test results back to their originating requirements to identify gaps between intended requirements and actual design outcomes.
• Impact Analysis for Requirement Changes: When requirements evolve, backward traceability reveals which design decisions, components, or implementations are affected so teams can assess the scope of changes before making them.
• Compliance Auditing: For regulated industries, backward traceability provides clear documentation showing how each design decision addresses specific regulatory or customer requirements.
• Root Cause Analysis: When design issues arise, teams can trace back from the problem to determine whether it stems from inadequate requirements, misunderstood specifications, or implementation gaps.

Best Practices for Long-Term Requirements Traceability

If we were to break down requirements traceability into the three core disciplines, these would be the main focus to reduce the number of potential design reworks. 

• Maintain Up-to-Date Records: Ensure that documentation is properly managed on a real-time basis. Without up-to-date requirements, procurement teams cannot properly manage quality assurance across a broad range of stakeholders. 
• Conduct Regular Requirements Reviews: Schedule periodic reviews with stakeholders to validate that requirements remain current, complete, and correctly interpreted throughout the design process. Reviews ensure traceability links remain accurate as requirements evolve and help identify gaps before they impact design decisions.
• Encourage Team Collaboration: More stakeholders involved means greater affinity for improvements, lower risks, and greater quality assurance. Proper requirements management begins internally, and with the right requirements traceability tools in place. 

A requirements traceability matrix is a valuable tool for electronic design projects looking to implement these best practices. It provides a structured framework that enables real-time documentation, stakeholder reviews, and cross-functional collaboration. By centralizing requirement relationships and implementation status, a requirements traceability matrix helps teams identify gaps, track changes, and ensure accountability across project phases.

Traceability in PCB Design

Requirements traceability in PCB design creates clear connections between design specifications and implementation decisions. Designers can trace component selections back to performance requirements and link layout choices to thermal or EMI specifications. Design changes maintain compliance with the original functional requirements.

Traceability also serves as a preventative tool in electronics product development. Engineers can assess the impact of proposed changes before implementation. Clear links between requirements and design elements enable proactive design management. 

How Does Requirements Traceability Reduce PCB Rework?

In electronics development, rework is the expensive process of modifying or redoing designs that have already been completed. Teams often need to rework electronics designs when design defects emerge, requirements are misinterpreted, or components fail to meet specifications. The need to rework electronics creates delays across engineering, procurement, and manufacturing.

Example

Consider a PCB design where power regulation caused overheating in a previous version. With requirements traceability, the design team can quickly identify that the fault stems from a voltage regulator that failed to meet the specified tolerance requirements.

Without a proper version history, the sourcing team might reorder the same inadequate component. Engineers may remain unaware of the true root cause. The issue could also originate from the supplier, requiring an investigation into component quality control.

However, with a clear understanding of the fault and history of previous parts and defects, requirements management can streamline the diagnosis of issues and avoid unnecessary rework.

Requirements Traceability in Altium

Altium's requirements and systems management capabilities give designers powerful requirements management tools. Requirements visibility is paramount for all stakeholders, which is why Altium prioritizes accessibility to ensure there are no barriers to design data. 

Altium's track and trace functions create a bird's eye view of the entire product lifecycle, creating and documenting a history of adaptations to any given design. Designers can automate their project updates to shared dashboards as they work and trace design elements back to the original product requirement. This minimizes the time between conceptualization and manufacturing while also providing a transparent overview of past changes.

Requirement history works in parallel with version control to compare and contrast designers' decisions. With this, Altium users can easily see which have been verified. 

Requirements traceability is the key to minimizing electronics design rework and saving time and money on costly investigations. Adhering to requirements traceability best practices, incorporating various stakeholder perspectives and sophisticated requirements management software help electronics design teams to diagnose issues quickly and accurately.