1. A method for determining a causative event in an information technology infrastructure comprising: collecting historical event data with a computer; generating an undirected graph, each node being an event and each edge being a probability of those events historically occurring simultaneously; reducing the undirected graph; determining graph adjacency of the undirected graph; generating a directed graph, each node being the event and each edge being the conditional probability of a second event occurring if the first event occurs; and from the directed graph, creating and outputting an historical list of recommendations to a user, the historical list of recommendations comprising an at least one event deemed to be the most likely causative event.