Predictability is an integral part of the software development cycle. It is useful for creating estimates, deadlines and development plans in a software project. However, software development is naturally unpredictable due to possible technical and other issues found during project execution. One way in which software processes can improve predictability is through the use of metrics in the test and repair process. Metrics can provide a way for progress of a project to be measured, allowing comparison to similar projects, which gives a greater sense on the progress of the project, system reliability and arguably thus customer satisfaction. These metrics are tested through simulation; using real data to trial different approaches for a projects test and repair stage. This report will model a set of ‘real world’ data, define a set of metrics and assumptions, and develop a simulation model.