This is supplemental data and code for: T. Proctor et al., Measuring the Capabilities of Quantum Computers, Nature Physics 18, 75-79 (2022). This folder contains all the data and the analysis code to generate the results presented in that paper. The core data analysis routines use PyGSTi, which can be found at https://github.com/pyGSTio/pyGSTi. Please direct any questions to Timothy Proctor (tjproct@sandia.gov).