Project Details Interdivisional Discussion of Critical Evaluation of Chemical Data

Project No.:
Start Date:
01 January 2017
End Date:
02 May 2018


To convene an open meeting during the IUPAC General Assembly (July 2017) to address the following questions

• How can IUPAC produce critical evaluations that are more useful to chemists and non-chemist users of chemical data?

• How can IUPAC adjust presentation formats and dissemination channels to make critically evaluated data more accessible to potential users?

• How can groups of critical evaluators within IUPAC better learn from one another’s experience?

• How can IUPAC identify overlooked data categories of high societal value for critical evaluation and organize efforts in response?

An open invitation for interested persons to attend will be sent to all Division Presidents and Committee Chairs and to additional individuals identified through networking as likely to be interested and available. An electronic forum will be maintained to allow preliminary communication among interested persons.


Exhaustive compilation from the primary chemical literature of property data for well defined systems and critical evaluation of the resulting data sets by international teams of experts has long been a IUPAC activity. Thus the current (as of November 2016) ‘Guidelines for IUPAC Projects’ states, “The core activity of IUPAC is to provide critical evaluations of methods and data and to make recommendations for nomenclature, terminology, metrology, and measurement standards.”

Prior to 2001, when IUPAC activities were organized around Commissions within the Divisions, a number of Commissions and Subcommittees within Commissions focused on critical evaluation and constituted an ongoing pool of expertise in critical evaluation of chemical data. As of 2001 groups with ongoing interests in critical evaluation of data included the Subcommittee on Thermodynamic Data (within the Commission on Thermodynamics, I.2), the Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry (within Commission on Chemical Kinetics, I.4), the Commission on Atomic Weights and Isotopic abundances, II.1, the Commission on Equilibrium Data, V.6, and the Commission on Solubility Data, V.8. (This list was compiled from the IUPAC Handbook 2000-2001, based on names of Commissions and Subcommittees. Errors and omissions, if any, are regretted.)

Since the reorganization of IUPAC to a project-driven organization, only two bodies have existed with continuing focus in compilation and critical evaluation of data–the Commission on Isotopic Abundances and Atomic Weights (II.1, under the Inorganic Chemistry Division) and the Subcommittee on Solubility and Equilibrium Data (SSED) within the Analytical Chemistry Division. Based on a review of the titles of active projects listed on the IUPAC web site in November 2016 it appears that three projects involving critical evaluation of data are underway in Division II, five in Division IV and 16 in Division V.

Although data compilation and evaluation has continued in IUPAC to the present, the breadth of such work has diminished. The reason seems clear. In parts of IUPAC without individuals having experience and interest in data compilation and evaluation needs for such projects may not be perceived or, when perceived, are deemed too difficult to address because of lack of experience. However, the full dimensions of this situation are unknown. Therefore it is appropriate to convene a meeting bringing together interested bodies and individuals to share information about plans and activities and to consider whether it would be useful to hold further meetings, possibly leading to a permanent structure to serve as an information clearing house. Critical evaluation of data and dissemination of data products to communicate evaluated data to users is a complex undertaking. We believe that the current organization of IUPAC in which these activities are organized along disciplinary lines is appropriate and should be maintained. We also believe that exchange of information and experience across disciplinary lines can be valuable and should be encouraged.

Expected Outcomes
We will prepare a meeting report and distribute this to attendees and other interested individuals. We will also prepare a short summary of the meeting for publication in Chemistry International. As appropriate, further communication will be maintained.


Sep 2017 update – An open meeting was held on 11 July 2017, pulling 14 attendees from all Divisions and from the Subcommittee on Cheminformatics Data Standards (SCDS). A meeting report is available pdf file 37 KB.

Summaries of current and recent activities in critical evaluation were presented by three groups within IUPAC active in data Evaluation
1. Critical Evaluation of Polymerization Kinetics Data (Subcommittee on Modeling of Polymerization Kinetics and Processes, Division IV)
Robin Hutchinson gave a PowerPoint presentation of this project which has been running for three decades. [See Slides – PDF 2MB]

2. Critical Evaluation of Isotopic Abundances and atomic weights (Commission on Isotopic Abundance Measurements and Atomic Weights, Division II)
Thomas Walczyk discussed this work with emphasis on the metrological approach to measurement uncertainty as described in two documents, The Guide to the Expression of Uncertainty in Measurement (the GUM) and The International Vocabulary of Metrology (the VIM). Further information is available at <>.

3. The Solubility Data Project (Subcommittee on Solubility and Equilibrium Data, Division V)
David Shaw gave a summary of the Solubility Data Series (SDS), a collection of compilations and critical evaluations of solubilities in various systems. The SDS has been an ongoing project since the 1970s producing more than 100 volumes evaluating published data for chemically well defined systems of gases in liquids, liquids in liquids and solids in liquids. Further information is available at <>.


The bulk of the meeting was a wide ranging discussion of participants’ experience, perspectives and challenges in critical evaluation. In this context several themes emerged. The goal of the meeting was to exchange ideas and perspectives; no attempt was made to reach consensus during the discussion. Consequently not all participants may agree with all thoughts expressed here.

• An essential goal of critical evaluation is to convey to data users, whatever their level of chemical sophistication, a well considered and supported estimate of the consensus value based on experimental results for the quantity under consideration and of the level of uncertainty surrounding that value. The metrological approach to the expression of uncertainty is an important tool in this context.

• Advances in computer-based handling of scientific data are leading to new possibilities for data manipulation and interpretation. These advances also present new challenges of providing information about the data (meta-data) in formats that are assessable to both humans and computers.

• The delivery of data to users is presently in flux because of continuing rapid changes in electronic methods of data aggregation analysis and presentation. It is essential to make evaluated data available through channels that potential users prefer or at least will actually use.

One topic not discussed during the meeting was whether meetings like this one should be repeated to encourage a continuing exchange of information and interdivisional projects. One form this could take would be an interdivisional working group or subcommittee on critical evaluation. The Task Group plans to discuss such possibilities with various interested parties and proceed as appropriate. Comments are welcome.


May 2018 update — Report published Chem Int April 2018, pp. 34-35 <>

Page last updated 2 May 2018