In order to obtain an unbiased estimate of the free energy change, the work distributions should overlap sufficiently (Figure ). In the case of poor overlap, the CFT result becomes the mean of forward and reverse exponential averages individually computed by the Jarzynski equality. As mentioned above, the exponential average is highly sensitive to the tails of the distribution and therefore, depending on the amount of sampling, a biased estimate. Thus, when overlap is poor, computed free energies are likely incorrect.