errors. Our approach differs in that we calculate the uncertainties (σ Current (∆ F k )) from the differences between independently-equilibrated replicate runs, rather than from intra-run fluctuations. To allow easy decomposition of the uncertainties into contributions from single states, increasing independence, we base our algorithm on the errors from TI rather than BAR. Theoretically, each set of repeat simulations at a given state can be run independently.