1. A method for estimating failure probabilities for resources in a production system, the method comprising: using at least one processor, maintaining a set of four count values for each of a plurality of resources in a production system, the four count values for each individual resource m including: a first count value m 11 indicating a number of plans where the resource m was used and failed, a second count value m 10 indicating a number of plans where the resource m was used and succeeded, a third count value m 01 indicating a number of plans where the resource m was not used and failed, and a fourth count value m 00 indicating a number of plans where the resource m was not used and succeeded; using the at least one processor, for each plan executed in the production system, incrementing a select one of the count values for each of the resources based on a list of resources used in the plan and the success or failure of the plan; using the at least one processor, for each resource, estimating a current fault probability value for single or multiple, persistent or intermittent faults based on at least one of the corresponding set of count values; and using the at least one processor, storing the current fault probability values for the resources.