Empirically, however, it has been found that the entropies calculated in equations 5 and 6 are overly biased towards doubly occupied orbitals. To adjust for this bias, a virtual orbital removal step is employed N times, in which the highest-entropy virtual orbital is removed from the sums in equations 5 and 6 and the entropies are recalculated; these highest-entropy virtual orbitals are then assigned the highest remaining entropy at the end of the calculation.