The bootstrap does not require a reformulation of estimators. Instead, a number, N b , of new data sets are created from the original data set (e.g., N b = 100 -1000) and the mean or median of variational scores on each of these data sets used. To create the bootstrapped data sets, trajectories are split into small independent subtrajectories. The subtrajectories are sampled with replacement to create a new bootstrapped data set of the same size as the original.