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CODATA (for Committee on Data, specifically the Committee on Data of the International Science Council) is an international initiative to collect, classify, and recommend determinations of fundamental physical constants, for the benefit of science and technology. Their recent practice has been to operate on a cycle: every four years, they collect and evaluate determinations (measurements) of fundamental constants, and publish recommended working values. In 2024, they published the results of their evaluation of determinations available in 2022, the result known as the CODATA 2022 values. In 2026, they will be gathering determinations through the year, and presumably when ready, similarly publish CODATA 2026 values. Among the values of special interest to astrophysics are:
Note the Boltzmann constant, Planck constant, electron volt, and speed of light in a vacuum are now all defined so the number of SI units is an exact decimal value: where practical, SI units are now defined in terms of physical constants in such manner. This doesn't eliminate the need to improve measurements of the constants: rather it indicates current determinations of the physical constants are now judged to be more accurate, precise, and consistent than other methods of defining these units.
National Institute of Standards and Technology (NIST), a United States government agency, aims to similarly coordinate standard working values for the USA's benefit. It adopts and publicizes the CODATA values, and contributes its own work in determining them.
CODATA is a branch of the International Science Council (ISC), an international organization carrying out a function somewhat similar to the International Astronomical Union (IAU), but dedicated to science in general. The IAU is a member organization if the ISC.