Uncertainty associated with virtual measurements from computational quantum chemistry models

A value for the measurand determined from a computational model is frequently referred to as a virtual measurement to distinguish it from a physical measurement, which is determined from a laboratory experiment. Any measurement, physical or virtual, is incomplete without a quantitative statement of its associated uncertainty. The science and technology of making physical measurements and quantifying their uncertainties has evolved over many decades. In contrast, the science and technology of making virtual measurements is evolving. We propose an approach for quantifying the uncertainty associated with a virtual measurement of a molecular property determined from a computational quantum chemistry model. The proposed approach is based on the Guide to the Expression of Uncertainty in Measurement, published by the International Organization for Standardization, and it uses the Computational Chemistry Comparison and Benchmark Database maintained by the National Institute of Standards and Technology.