c. Data standards

Data standards need to be considered at two levels: ‘standards for data elements’ and ‘form standards’. This will help to make your data interoperable and re-usable: if your data is well-standardised, it can readily be combined with data from different collections and studies.

Standards for data elements

There are international standards that define the meaning of data elements. For instance, a standard may define the concept of ‘gender’ or ‘body weight’. These standards also provide codes that allow computers to process the data elements. In addition, they may contain a code value list or response options for a particular concept (e.g., option 'female' for the concept 'gender').

Mapping your data elements to concepts in existing terminologies requires quite some expertise and effort. It is therefore recommended to reuse mapped data elements from existing studies in the same domain whenever possible. For more complex studies, we advise you to consult an expert in data mapping. Describe your chosen standards in a codebook.

'Form' standards

Form standards describe which data elements 'logically' belong together and can be grouped as one form. Examples of form standards are:

  • demographics (e.g., birth rate and ethnicity);
  • adverse events (e.g., date of disease onset; type and grade of disease).

Frequently Asked Questions

A terminology is a standardised list of terms that are used in a particular domain. The terms are organised by concept. There are different types of terminologies:

  • code system, where concepts are associated with a code;
  • thesaurus, where terms are ordered systematically or alphabetically;
  • classification, where concepts are ordered hierarchically, so each concept is grouped with similar concepts in a particular class;
  • vocabulary (also called ontology), where concepts are defined with hierarchical and non-hierarchical relations;
  • nomenclature, a type of vocabulary that also defines a syntax with which you can express concepts that are not (yet) part of the nomenclature.

The standard terminologies tend to offer support for multiple languages, although Dutch is implemented only to a limited extent. Language is therefore still a relevant consideration at the start of your study. The crowd-sourced WikiData offers many translations. HPO also provides laymen translations in several languages.