Described are a system and method for identifying variables which impact performance of software under development. Data is collected that is related to performance characteristics of the software under development. Performance change gradients are determined between previous builds of the software under development. A set of performance change factors are generated from the collected data that corresponds to each performance change gradient. Performance characteristic data corresponding to a current build of the software under development are compared to the performance change gradients. At least one fault component from the set of performance change factors that influences performance of the current build is output in response to the comparison between the performance characteristic data corresponding to the current build and the plurality of performance change gradients.