1. A method using a completed corrective action as evidence of a fault by a diagnostic reasoner, comprising: receiving equipment status evidence; determining an equipment fault based on the equipment status evidence; creating and ranking a list of potential failure modes based at least in part on the determined equipment fault; recommending a corrective action to correct the equipment fault based at least in part on the ranking of the potential failure modes; receiving additional equipment status evidence indicating that the recommended corrective action failed to correct the equipment fault; associating a detection probability and a false negative rate with the failed corrective action to create additional status evidence wherein the false negative rate is equal to a ratio, wherein the numerator of the ratio is equal to the number of times the corrective action was performed on a valid equipment fault minus the number of times the corrective action corrected the valid equipment fault, and the denominator is the number of times the corrective action was performed on a valid equipment fault; and re-ranking the list of potential failure modes for recommendation of a subsequent corrective action to be performed based on the additional status evidence.