---
title: "What is Traceability?"
description: "Understanding requirements traceability and its importance in software development"
---

# What is Traceability?

**Requirements traceability** is the ability to describe and follow the life of a requirement throughout the entire development lifecycle - from its origin through design, implementation, testing, and deployment.

## Definition

Traceability provides a documented chain that connects:

```
STAKEHOLDER NEED → REQUIREMENT → DESIGN → CODE → TEST → DEPLOYMENT
```

Each link in this chain answers important questions:

| Link | Question Answered |
|------|-------------------|
| Need → Requirement | Why does this requirement exist? |
| Requirement → Design | How will this be structured? |
| Design → Code | Where is this implemented? |
| Code → Test | Is this verified? |
| Test → Deployment | Is this ready for release? |

## Types of Traceability

### Forward Traceability

Traces from requirements **forward** to implementation and testing:

```
REQUIREMENT → CODE → TEST
```

**Purpose**: Ensure every requirement is implemented and tested.

**Key Question**: "Is this requirement covered?"

### Backward Traceability

Traces from implementation **backward** to requirements:

```
TEST → CODE → REQUIREMENT
```

**Purpose**: Ensure every piece of code and test has a purpose.

**Key Question**: "Why does this code/test exist?"

### Bidirectional Traceability

Combines forward and backward traceability:

```
REQUIREMENT ←→ CODE ←→ TEST
```

**Purpose**: Complete visibility in both directions.

**Key Question**: "What's the full picture?"

## The Traceability Matrix

The Requirements Traceability Matrix (RTM) is the primary deliverable:

```
                         TESTS
                    T-001  T-002  T-003  T-004
REQUIREMENTS        ────────────────────────────
REQ-001 Login         ✓      ✓                    [2 tests]
REQ-002 Logout        ✓                           [1 test]
REQ-003 Password            ✓      ✓      ✓      [3 tests]
REQ-004 Profile                                   [0 tests] ⚠
────────────────────────────────────────────────
Coverage             75%   (3/4 requirements have tests)
```

The matrix reveals:
- **Coverage**: REQ-004 has no tests (gap)
- **Over-testing**: REQ-003 has 3 tests (may be appropriate for critical features)
- **Relationships**: T-002 covers multiple requirements

## Why Traceability Matters

### 1. Completeness Verification

Without traceability, you can't answer:
- Are all requirements implemented?
- Are all requirements tested?
- Are there orphan tests (tests without requirements)?

### 2. Impact Analysis

When a requirement changes:
- What code needs to change?
- What tests need updating?
- What other requirements are affected?

```
If REQ-001 changes:
├── CODE-001 (implements REQ-001) → needs review
├── CODE-002 (implements REQ-001) → needs review
├── TEST-001 (tests REQ-001) → needs update
└── REQ-005 (depends on REQ-001) → needs review
```

### 3. Compliance & Audits

Regulated industries require proof that:
- Every requirement has an origin (business justification)
- Every requirement is implemented
- Every requirement is tested
- All changes are tracked

### 4. Change Management

Before approving a change request:
- What's the scope of impact?
- What's the effort required?
- What's the risk?

### 5. Project Visibility

At any time, stakeholders can ask:
- What's the coverage percentage?
- What requirements are at risk?
- What's blocking release?

## Real-World Example

Consider a banking application with a requirement:

**REQ-042**: "Users must be able to transfer funds between accounts"

With traceability:

```
Business Need (BN-012): "Enable self-service banking"
    └── REQ-042: "Users must transfer funds"
            ├── DESIGN-018: "Transfer Service Architecture"
            │       └── CODE-089: transfer_service.py
            │               ├── TEST-201: test_transfer_valid_amount
            │               ├── TEST-202: test_transfer_insufficient_funds
            │               └── TEST-203: test_transfer_daily_limit
            └── DESIGN-019: "Transfer UI Wireframe"
                    └── CODE-090: TransferForm.tsx
                            └── TEST-210: test_transfer_form_validation
```

Now if REQ-042 changes (e.g., "add international transfers"):
1. Impact analysis shows exactly what's affected
2. QA knows which tests need updating
3. Developers know which code to modify
4. Managers can estimate effort accurately

## Traceability vs. Tracking

| Traceability | Tracking |
|--------------|----------|
| Relationships between artifacts | Status of individual items |
| "What's connected to what?" | "What's the status?" |
| Graph structure | List/table structure |
| Answers "why" and "what if" | Answers "where is it" |

Both are important, but traceability provides deeper insights.

## Common Traceability Challenges

### 1. Link Rot

Links become stale when:
- Code is refactored without updating links
- Requirements change without updating tests
- Items are deleted without updating dependents

**Solution**: Automated validation, link integrity checks

### 2. Over-Tracing

Too many links create noise:
- Every function linked to every requirement
- Generic "related to" links everywhere

**Solution**: Use semantic link types, trace at appropriate granularity

### 3. Under-Tracing

Too few links create gaps:
- Critical requirements without test links
- Code without requirement justification

**Solution**: Coverage reports, gap analysis, mandatory linking rules

### 4. Manual Maintenance

Keeping traceability up-to-date manually is:
- Time-consuming
- Error-prone
- Often abandoned

**Solution**: Automation, CI/CD integration, agent-based linking

## Traceability in TraceRTM

TraceRTM makes traceability practical:

```python
from tracertm import TraceRTMClient

client = TraceRTMClient()

# Create requirement
req = client.create_item(
    title="User Authentication",
    item_type="feature"
)

# Create test and link
test = client.create_item(
    title="Test Login Flow",
    item_type="test"
)
client.create_link(test.id, req.id, "tests")

# Check coverage
coverage = client.get_test_coverage()
print(f"Coverage: {coverage.percentage}%")

# Impact analysis
impact = client.analyze_impact(req.id)
print(f"Affected items: {impact.total_count}")
```

## Industry Standards

Traceability is required or recommended by:

| Standard | Industry | Requirement |
|----------|----------|-------------|
| DO-178C | Aerospace | Mandatory bidirectional traceability |
| ISO 26262 | Automotive | Safety requirements traceability |
| IEC 62304 | Medical Devices | Software requirements traceability |
| FDA 21 CFR Part 11 | Pharma/Medical | Audit trail requirements |
| ISO 27001 | Security | Change management traceability |

## Getting Started

1. **Start Simple**: Begin with requirement → test links
2. **Add Design**: Include architecture and design artifacts
3. **Connect Code**: Link implementation to requirements
4. **Automate**: Use CI/CD to maintain links
5. **Report**: Generate matrices and coverage reports

## Next Steps

- [Types of Traceability](/docs/wiki/concepts/traceability/types) - Deep dive into trace types
- [Benefits](/docs/wiki/concepts/traceability/benefits) - ROI of traceability
- [Best Practices](/docs/wiki/concepts/traceability/best-practices) - Industry guidance
- [Your First Project](/docs/getting-started/first-project) - Hands-on tutorial

