The BUQEYE Collaboration aims to use statistical tools to answer fundamental problems in the construction and application of effective field theories (EFTs), with particular attention to low-energy nuclear physics. This includes Bayesian parameter estimation, model checking, model selection, and experimental design. We also develop emulators to facilitate these applications.

We have proposed and tested a Bayesian model of truncation errors, which is often the dominant source of errors for EFTs. Meaningful uncertainty quantification (UQ) allows physicists to compare theory to experiment, but we have also shown that it provides a useful metric to avoid overfitting the parameters the EFT and to validate that the EFT is working as expected. Specific applications are to chiral EFT, pionless and halo EFT, and to electroweak processes in all cases.

**Congratulations:** BUQEYE Jordan Melendez was selected to receive the American Physical Society’s 2021 Dissertation Award in Nuclear Physics for his thesis: *Effective Field Theory Truncation Errors and Why They Matter*. This thesis is a great introduction to BUQEYE technology.

*Supported in part by the US Department of Energy, the National Science Foundation, and the SciDAC NUCLEI-3 project.*