Abstract: A system and method for calculating the performance of a cluster tool using a weighted configuration matrix. The system includes a computer system which maintains a database of entities corresponding to semiconductor wafer processing modules in a fab. A user "clusters" the entities, i.e., selects entities to reflect the relationship of the constituent modules physically linked together which form the cluster tool. The user also designates a main module against which the main performance events of the cluster tool, such as begin run and end run, are logged in the database. The computer system configures all of the "up" and "down" state configuration combinations of the cluster tool modules and displays the configurations for the user. The user specifies a weight for each of the configurations based upon an estimate of the performance the cluster tool while in the respective configuration relative to the performance of the cluster tool in a fully operable configuration.