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International Measurement Database Goes Online

Measurement-related questions and disputes, including those that can hinder global commerce, soon may be resolved with a click of a computer mouse thanks to a new international database of measurement comparisons unveiled this week by the National Institute of Standards and Technology, an agency of the U.S. Department of Commerce's Technology Administration, and the International Bureau of Weights and Measures (also known as BIPM) in Sèvres, near Paris, France.

Developed by NIST, the Internet-accessible International Comparisons Database will enable companies, regulators and others to evaluate the equivalence of calibrations and other measurement services performed by national metrology institutes (known as NMIs) in nearly all parts of the globe. In turn, the database will make it easier for businesses and other organizations that rely on these services to prove compliance with the measurement-related requirements of regulations and standards, which affect an estimated 80 percent of global product trade.

"This database of measurement comparisons will be an integral part of the infrastructure necessary to expand free trade and to eliminate technical barriers to export markets," said NIST Director Ray Kammer. "It advances the goal of 'measured once, accepted everywhere.' Measurement traceability on a global basis should help to reduce redundant product testing."

The database was one of the key action items in a 38-nation accord calling for "mutual recognition of national measurement standards," signed in October during the quadrennial meeting of the General Conference on Weights and Measures. In anticipation of the agreement, NIST began designing the comparisons database in early 1998. BIPM joined the effort in 1999, providing the data for over 240 key and supplementary comparisons.

The so-called arrangement established a formal system of "key" measurement comparisons among the NMIs, or chief measurement organizations, of the signer nations. These multinational exercises determine how closely a particular measurement (of voltage, length or mass, for example) performed by one NMI agrees with results achieved by other participating NMIs.

Comparisons provide the basis for estimating the degree of equivalence between the measurement results of NMIs. High levels of agreement foster confidence in measurement-related transactions between international trading partners.

Initially, the new database will record and display results of completed and ongoing key comparisons among the NMIs of nations that signed the October mutual recognition pact. About 130 of these round-robin measurement exercises are now under way, according to BIPM, which is responsible for promoting use of the international system of measurements and for furthering the system's development. International teams of measurement experts will evaluate the reliability of the results before entering them into the database.

Later, the database will be expanded to include all other NMIs through their participation in any one of the world's six regional metrology organizations, explained Robert Watters, Jr., the NIST scientist who led the database-development team. The International Comparisons Database can be accessed from the BIPM Web site at It also can be viewed on the NIST Web site at

As a non-regulatory agency of the U.S. Department of Commerce's Technology Administration, NIST strengthens the U.S. economy and improves the quality of life by working with industry to develop and apply technology, measurements and standards through four partnerships: the Measurement and Standards Laboratories, the Manufacturing Extension Partnership, the Advanced Technology Program, and the Baldrige National Quality Program.

Released December 2, 1999, Updated February 2, 2023