Single source of truth(Q7523885), often abbreviated as SSOT/SPOT (a.k.a. Single Point of Truth) is a discipline or pragmatic approach to store data in only one abstract place. This one place, doesn't mean that the data has only one copy, but the way data being retrieved and presented are always going through a single channel(See 3-2-1 Backup Rule )^[1], often managed by a version control system.

Excerpts from Wikipedia

In information science and information technology, single source of truth (SSOT) architecture, or single point of truth (SPOT) architecture, for information systems is the practice of structuring information models and associated data schemas such that every data element is mastered (or edited) in only one place, providing data normalization to a canonical form (for example, in database normalization or content transclusion). Any possible linkages to this data element (possibly in other areas of the relational schema or even in distant federated databases) are by reference only. Because all other locations of the data just refer back to the primary "source of truth" location, updates to the data element in the primary location propagate to the entire system, providing multiple advantages simultaneously: greater efficiency/productivity, easy prevention of mistaken inconsistencies (such as a duplicate value/copy somewhere being forgotten), and greatly simplified version control. Without SSOT architecture, rampant forking impairs clarity and productivity, imposing laborious maintenance needs.

Deployment of an SSOT architecture is becoming increasingly important in enterprise settings where incorrectly linked duplicate or de-normalized data elements (a direct consequence of intentional or unintentional denormalization of any explicit data model) pose a risk for retrieval of outdated, and therefore incorrect, information. Common examples (i.e., example classes of implementation) are as follows:

• In electronic health records (EHRs), it is imperative to accurately validate patient identity against a single referential repository, which serves as the SSOT. Duplicate representations of data within the enterprise would be implemented by the use of pointers rather than duplicate database tables, rows, or cells. This ensures that data updates to elements in the authoritative location are comprehensively distributed to all federated database constituencies in the larger overall enterprise architecture. EHRs are an excellent class for exemplifying how SSOT architecture is both poignantly necessary and challenging to achieve: it is challenging because inter-organization health information exchange is inherently a cybersecurity competence hurdle, and nonetheless it is necessary, to prevent medical errors, to prevent the wasted costs of inefficiency (such as duplicated work or rework), and to make the primary care and medical home concepts feasible (to achieve competent care transitions).
• Single-source publishing as a general principle or ideal in content management relies on having SSOTs, via transclusion or (otherwise, at least) substitution. Substitution happens via libraries of objects that can be propagated as static copies which are later refreshed when necessary (that is, when refreshing of the copy-paste or import is triggered by a larger updating event, such as a new scientific advance or a piece of breaking news). Component content management systems are a class of content management systems that aim to provide competence on this level.

Ideally, SSOT systems provide data that are authentic (and authenticatable), relevant, and referable.

The Entropy Pool

To relate Single source of truth in physical reality, the notion of a shared clock, or more technically, the idea of a common entropy pool, is essential to achieve this goal. A well-known example in setting up one large entropy pool is Bitcoin's blockchain.