1. A computer-implemented method for explaining a recommendation produced by a decision support tool comprising: using a computer system, submitting a list of observation inputs to a decision support tool to produce a recommendation; using a computer system, reordering the list of observation inputs according to an observation metric; and using a computer system, quantifying how each observation input impacts the probability of the recommendation produced by: sequentially applying inputs from the reordered list of inputs to the decision support tool; and measuring the change in probability of the recommendation for each input with an explanation metric.