To see how our ΔΔG values compared with clinical resistance measurements, we calculated an estimated 'expected ΔΔG' corresponding to the geometric mean of MICs associated with each of the resistance conferring mutations, using previously described methods . However, the errors in both the 'expected ΔΔG' and the ΔΔG values calculated by RBFE were too large to enable us to draw any conclusions about how well the values compare with one another (Fig. ).