HSE Data Dictionary

The HSE is developing a Data Dictionary in order to standardise all data elements throughout the organisation. This Data Dictionary will allow the HSE to derive information based on standards for better patient care and outcomes. However, currently, information that is collected is difficult to analyse and interpret. Access to and analysis of health information is important.  It provides opportunities to gain valuable insights into how we can deliver safe effective and equitable health for all, build knowledge on health and wellbeing, and inform planning of our health services.

We are building an information structure with detailed definitions of information to support the effective processing of information (clinical and business) within Technology and Transformation.  A core building block of this information structure is a National Data Dictionary which will provide a single standardised platform accessible to all individuals in Ireland. 

Our core business revolves around metadata standardisation, the national data dictionary, metadata modelling, glossaries, catalogues, metadata governance and structured content publication.

A Data Dictionary is a collection of names, definitions, and attributes about data elements that are being used or captured in a database, information system, or part of a research project. It describes the meanings and purposes of data elements within the context of a project, and provides guidance on interpretation, accepted meanings and representation. A Data Dictionary also provides metadata about data elements. The metadata included in a Data Dictionary can assist in defining the scope and characteristics of data elements, as well the rules for their usage and application. 


Metadata often described as data about other data.  It is information about how data is defined, structured and represented. It makes data files meaningful by describing the information captured in data, and how it is measured and represented.

The role of a Data Dictionary is to standardise definitions that can be conformed to across Technology and Transformation applications. Figure 1 below shows ISO 11179, the International Standard that gives us a framework that we can use for describing data definitions and datasets.  A metadata registry that has been created based on the ISO 11179 standard can show the relationships between data elements and the data sets and can also show how frequently a data element is included in data sets.

        ISO 11179


The National Data Dictionary can act as a reference point for approved information.

Terminologies and Classifications

Various clinical terminologies and classification standards such as SNOMED CT and ICD10 are currently in use in Ireland.  We will include the Irish edition of SNOMED CT in the data dictionary so this data can act as a reference point for sharing approved information between service providers.


Data Stewardship is a consideration for groups managing data within the organisation. Stewards are users who are responsible for maintaining metadata.  All endorsed or published metadata is managed by data stewards who are responsible for keeping it up to date. They are trusted users with the permission to update all metadata in the workgroup.

Business functions consider who has responsibility for deciding the enterprise definition for a term. Agreed business metadata will be included in the data dictionary so that this information can be integrated into health and social care delivery in accordance with Technology and Transformation, HSE.

In order to ensure data standardisation, the HSE have established the Dataset Specification Management Process (DSMP). The DSMP process and group were developed to provide a forum and process to enable stakeholders who have a role in the management and analysis of health information systems data.  The benefits of the DSMP are to ensure a standardised uniform process that facilitates new and existing dataset specification and to have a quality assurance process for new and existing dataset specifications.

For more information on the DSMP go to the Dataset Specification Management Process webpage or contact  Yvonne.Coughlan2@hse.ie 

For more information on the Data Dictionary contact nhscdd@hse.ie or denise.dawe@hse.ie





Updated: 06/12/2022