Predicting Component Failures at Early Design Time

For the effective prevention and elemination of defects and failures in a software system, it is important to know which parts of the software are mor likely to contain errors, and therefore, can be considered as "risky". To increase reliability and quality, more effort should be spent in risky components during design, implementation, and testing. Examining the version archive and the code of a large open-source project, we have investigated the relation between the risk of components as measured by post-release failures, and different code structures; such as method calls, variables, exception handling expressions and inheritnace statements. We have analyzed the different types of usage relations between components, and their affects on the failures. We utilized three commonly used statistical techniques to build failure prediction models. As a realistic opponent to our models, we introduced a "simple prediction model" which makes use of the riskiness information from the available components, rather than making random guesses. While the results from the classification experiments supported the use of code structures to predict failur-proneness, our regression analyses showed that the design time decisions also effected component riskiness. Our models were able to make precise predictions, with even only the knowledge of the inheritnace relations. since inheritance relations are defined aerliest at design time; based on the results of this study, we can say that it may be possible to initialize preventive actions against failures even early in the design phase of a project