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Digital Representation of Units of Measurement (DRUM)

Members of the Task Group

  • Robert Hanisch, NIST, USA (Chair)
  • Stuart Chalk, University of North Florida, USA; and IUPAC (Secretary)
  • Simon Cox, CSIRO, Australia (Member and TG Liaison)
  • Steven Emmerson, UCAR, USA (Member)
  • Jeremy Frey, University of Southampton, UK; and IUPAC (Member)
  • Maximilian Gruber, PTB, Germany (Member)
  • Pascal Heus, Canada (Member)
  • Joachim Meier, PTB, Germany (Member)

Liaisons, CODATA Executive Committee

  • Richard Hartshorn, University of Canterbury, NZ; and IUPAC
  • Toshihiro Ashino, Toyo University, Japan

Mission and Objectives

The objective of this task group is to work with the International Science Unions to raise awareness of, educate, and enable their communities in the understanding and implementation of digital unit representation. This will be done with reference to each of the three objectives of the CODATA Decadal Programme, namely:

  • Enabling Technologies and Good Practice for Data-Intensive Science
  • Mobilising Domains and Breaking Down Silos
  • Advancing Interoperability Through Cross-Domain Exemplary Case Studies

Each of the above objectives can be addressed by awareness of the different units of measurement representations that are currently available (see the inventory developed in the 2018 – 2021 TG). This, coupled with the movement toward FAIR data, will be used to promote the idea that units of measurement are not second class citizens in science, but rather the most important aspect of what is needed to make data FAIR.


Every measurement made where a numerical value is generated requires the recording of and association with a unit of measurement.  In the current research environment, where the paradigm is shifting to the digital publication of research data in openly accessible formats, researchers annotate a unit of measurement by adding a string of characters to a numeric value in a computer system (database, spreadsheet, text file etc.). While the researcher may well report the unit in a common unit system (e.g. the SI) the guidelines for formatting these strings (e.g., BIPM, ISO, NIST) are often not followed. As a result, there is a significant problem in normalization of units and this is a significant barrier to the interoperability of data.

Impact (Outcomes and Achievements)

  • Recommendations for FAIR compliant, machine actionable encoding of units of measurement
    in different scenarios (e.g. typesetting, spreadsheet, database, webpage)
  • Guidelines for the annotation of data with a unit of measurement in digital systems
  • Best practices for adopting and implementing the recommended DRUM system
  • A Units of Measure Interoperability Service (UMIS) to enable unit web services

Planned Activities and Outputs

Across the International Scientific Unions (ISUs) (and affiliated organizations) there is a variety of expertise in this area in addition to technical resources on units available online.  This task group will focus on:

  • A coordinated articulation of the appropriate way to treat units of measurement (and other metrology concepts) in the digital representation of scientific data
  • Guidance and tools to enable:
    • ISU’s to develop paths toward normalization of units within a discipline
    • Digital repository developers to provide users services around units for data ingestion and exposure
    • Research scientists to annotate data with a unit ‘at birth’ that is unambiguous
    • Software vendors and developers to use consistent and compatible units in scientific data file formats
    • Journal Publishers to automate the checking of units in scientific papers and datasets
    • Educational Publishers to systematically represent units in texts
  • Producing a recommendation on the use of units in digital systems, in different usage situations, that enables unit interoperability
  • Guidelines for the annotation of data with a unit of measurement in digital systems
  • Best practices for adopting and implementing digital unit representation systems
  • Task group page(s) outlining the activities, materials, and outcomes of the task group
  • ‘Metrology 101’ educational resource to present the concepts in metrology to students, scientists, and the general public across all ages and geographic regions
  • A Units of Measure Interoperability Service (UMIS) – web service supporting unit interoperability
  • Two annual meetings of the task group members with presentations by members of the ISU’s
  • Through liaison with the Digital SI Expert Group, recommendations to BIPM from the scientific community on the digital representation of units of measurement

Assigning values to characteristics or qualities of things in the world, which includes nominal values, classifications, ordering, as well as quantitative measurements which are scaled with units. ‘Scales’ for nominal values are sometimes called ‘controlled vocabularies’ or ‘code-lists’; ordinal scales are things like the geological timescale, in which ordering relationships are fixed, even as the temporal position is continuously adjusted due to better characterization of the chronometric scale; taxonomies (in the biological sense) are a kind of hierarchical classification.