The fundamental constants and theory

The Committee on Data for Science and Technology has recently recommended a new self-consistent set of values of basic constants and conversion factors of physics and chemistry. These values are based on a least-squares analysis that takes into account all of the latest relevant experimental and theoretical information in a consistent framework. Theory plays a role, because the experimental data are compared to the corresponding theoretical predictions which are functions of the fundamental constants. The best values of the constants are taken to be those that give the best agreement between the data and these predictions, in the least-squares sense. An overview of the calculations that influence the recommended values of the constants will be given.