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# Source of Truth

> The agreed answer an organisation uses for a given piece of information, whether that answer comes directly from an authoritative system or from a reconciled record built from several systems.

## Definition

The answer an organisation has agreed to use for a given piece of information. It may be supplied
directly by the system designated as authoritative, or it may be a reconciled value assembled from
several systems. The term describes the agreed answer, not the mechanism that produces it.

## Expanded Explanation

The phrase is used loosely across the industry, which is why the tieback Knowledge Base separates it
from two adjacent terms. A system of record is a designated place. An authoritative source is a
competent, accountable origin for a value. A source of truth is the resulting answer that downstream
processes and publications are required to use.

In simple cases the three coincide. If one system is designated authoritative for a product weight
and nothing else competes with it, that system is also the source of truth for weight. In more
common cases they diverge: three systems hold a material composition, one is authoritative for the
engineering value, another carries the supplier declaration, and the agreed answer is a reconciled
golden record built from both under defined rules.

The related phrase "single source of truth" describes an aspiration rather than an architecture: one
agreed answer per attribute, consistently used everywhere. It should not be read as a requirement to
hold all product information in one physical system. Federated architectures achieve a single source
of truth by agreeing where each answer comes from, not by centralising storage.

## Why It Matters

A Digital Product Passport publishes one value per field. Deciding that value is a governance
question before it is a technical one. Organisations that leave it undecided discover the decision
has been made implicitly by integration order, and that two published passports for related products
can disagree with each other while both are technically working as built.

## Common Misconceptions

#### A single source of truth means a single system

It means a single agreed answer. Most manufacturers reach that state across several systems by
designating authority per attribute and reconciling deliberately.

#### Source of truth and system of record are interchangeable

A system of record is where authority sits. A source of truth is the answer that results. They
differ whenever more than one system holds the same attribute.

## Related Terms

* [System of Record](/docs/knowledge-base/glossary/system-of-record)
* [Authoritative Source](/docs/knowledge-base/glossary/authoritative-source)
* [Golden Record](/docs/knowledge-base/glossary/golden-record)
* [Master Data Management](/docs/knowledge-base/glossary/master-data-management)

## Related Knowledge Base Articles

* [What is a System of Record?](/docs/knowledge-base/enterprise-systems-and-data-architecture/what-is-a-system-of-record)
* [What is a Golden Record?](/docs/knowledge-base/enterprise-systems-and-data-architecture/what-is-a-golden-record)
* [How Enterprise Systems Support Digital Product Passports](/docs/knowledge-base/enterprise-systems-and-data-architecture/how-enterprise-systems-support-digital-product-passports)

## Related Articles

* [Authoritative Source](/docs/knowledge-base/glossary/authoritative-source)
* [Product Data Governance](/docs/knowledge-base/glossary/data-governance)
* [Product Data Stewardship](/docs/knowledge-base/glossary/data-stewardship)
* [System of Record](/docs/knowledge-base/glossary/system-of-record)
* [Golden Record](/docs/knowledge-base/glossary/golden-record)
* [Product Data Quality](/docs/knowledge-base/glossary/data-quality)
* [Data Architecture](/docs/knowledge-base/glossary/data-architecture)
* [Master Data Management](/docs/knowledge-base/glossary/master-data-management)

## See Also

* [Enterprise Systems and Data Architecture](/docs/knowledge-base/enterprise-systems-and-data-architecture/overview)
* [Implementation](/docs/knowledge-base/implementation/overview)

## References

* Regulation (EU) 2024/1781, Official Journal of the European Union:
  [https://eur-lex.europa.eu/eli/reg/2024/1781/oj](https://eur-lex.europa.eu/eli/reg/2024/1781/oj)
* ISO 8000, data quality: [https://www.iso.org/standard/81745.html](https://www.iso.org/standard/81745.html)

## About This Article

About This Article

<dl>
  <dt>
    Last Reviewed
  </dt>

  <dd>
    2026-08-09
  </dd>

  <dt>
    Next Scheduled Review
  </dt>

  <dd>
    2027-08-09
  </dd>

  <dt>
    Article Version
  </dt>

  <dd>
    1.0
  </dd>
</dl>

tieback Knowledge is a continuously maintained reference library covering Digital Product
Passports, product traceability, product compliance and related regulations. Articles are
reviewed regularly as legislation, standards and implementation guidance evolve.

## Related Docs

* [Enterprise Systems and Data Architecture](/docs/knowledge-base/enterprise-systems-and-data-architecture/overview)
* [Implementation](/docs/knowledge-base/implementation/overview)
* [Digital Product Passports](/docs/knowledge-base/digital-product-passports/overview)
* [Glossary](/docs/knowledge-base/glossary/overview)