Estimating fixing effort and schedule based on defect injection distribution

Detecting and fixing defects are key activities in a testing process, which consume two kinds of skill sets. Unfortunately, many current leading software estimation methods, such as COCOMO II, mainly estimate the effort depending on the size of software, and allocate testing effort proportionally among various activities. Both efforts on detecting and fixing defects, are simply counted into software testing process/phase and cannot be estimated and managed satisfactorily. In fact, the activities for detecting defects and fixing them are quite different and need differently skilled people. The inadequate effort estimation leads to the difficulty of test process management. It is also the main problem which causes software project delays. In this article, we propose a method on Quantitatively Managing Testing (TestQM) process including identifying performance objectives, establishing a performance baseline, establish a process-performance model for fixing effort, and establishing a process-performance model for fixing the schedule, which supports high-level process management mentioned in Capability Maturity Model Integration (CMMI). In our method, defect injection distribution (DID) is used to derive estimation of fixing effort and schedule. The TestQM method has been successfully applied to a software organization for their quantitative management of testing process and proved to be helpful in estimating and controlling defects, effort and schedule of the testing process. Copyright  2008 John Wiley & Sons, Ltd.