Commission on Crystallographic Nomenclature

Statistical descriptors in crystallography

1995 report - authors and abstract

Acta Cryst. (1995). A51, 565-569[pdf icon]

Statistical Descriptors in Crystallography. II. - Report of a Working Group* on Expression of Uncertainty in Measurement

  • D. Schwarzenbach (Chairman), Institut de Cristallographie, University of Lausanne, BSP, CH-1015 Lausanne, Switzerland,
  • S. C. Abrahams (ex officio, IUCr Commission on Crystallographic Nomenclature), Physics Department, Southern Oregon State College, Ashland, OR 97520, USA,
  • H. D. Flack, Laboratoire de Cristallographie aux Rayons X, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Genève 4, Switzerland,
  • E. Prince, National Institute of Standards and Technology, Reactor Radiation Division, Gaithersburg, MD 20899, USA, and
  • A. J. C. Wilson (ex officio, IUCr Commission on Crystallographic Nomenclature), St John's College, Cambridge CB2 1TP, England.
(Received 18 August 1994; accepted 15 December 1994)

The Working Group has examined recent recommendations for evaluating and expressing uncertainty in measurement [Guide to the Expression of Uncertainty in Measurement, International Organization for Standardization (ISO, 1993)]. The present publication updates an earlier report of the IUCr Subcommittee on Statistical Descriptors [Schwarzenbach, Abrahams, Flack, Gonschorek, Hahn, Huml, Marsh, Prince, Robertson, Rollett & Wilson, (1989). Acta Cryst. A45, 63-75]. This new report presents the concepts of standard uncertainty, of combined standard uncertainty, and of type A and type B evaluations of standard uncertainties. It expands the earlier dictionary of statistical terms, recommends replacement of the term estimated standard deviation (e.s.d.) by standard uncertainty (s.u.) or by combined standard uncertainty (c.s.u.) in statements of the statistical uncertainties of data and results, and requests a complete description of the experimental and computational procedures used to obtain all results submitted to IUCr publications.

* Appointed 4 March 1993 as a Working Group of the International Union of Crystallography Commission on Crystallographic Nomenclature. The final report of the Working Group was accepted on 20 September 1994 by the Commission and on 15 December 1994 by the Executive Committee.
© 1989, 1995 International Union of Crystallography
Updated 18th Sept. 1996

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