Because BLUES includes intervals of both MD and NCMC, we consider the total number of force evaluations resulting from each simulation type when comparing with MD rather than comparing the total simulation time run. In terms of wallclock time, this may not be strictly comparable -e.g. alchemical perturbations in NCMC can incur some additional costs relative to force evaluations in standard MD, but also can be made faster by holding some parts of the system fixed. However accounting for force evaluations still provides a good starting point for examination of efficiency.