Total quality assurance cost in this scenario will be:
\begin{equation} \label{cprim}C_{total}^{\prime}{}=\sum C_{phase}^{\prime}{}=524x+522x+347x=1393x\\ \end{equation}

Cost of investment

Costs of defect prediction introduction were calculated as the sum of such elementary costs:
Tool acquisition and installation costs of the case investigated shall be considered as zero costs. In Volvo’s organization, DePress is freely available via an internal application installation system called FAROS. DePress can be ordered and installed on user’s computers without any additional costs for the project.
Training time costs – support of DePress and defect prediction is handled by their internal Development & Runtime Support organization, which is already pre-paid by project, whether such a tool and technology will be used or not. Due to that fact, any training cost is the cost per man-hour for each developer, which will be responsible for the analysis. After measuring time spent on training a single person, we can state that: a developer needs to spend a maximum of 4 hours on training, 1-2 hours of general introduction plus another 1-2 hours of training in prediction preparation.
Data collection cost is mostly the man-hour cost of exporting the proper data from data sources and code metrics generation for two selected releases. Data export, if used (direct-connection DePress nodes also can be used, which will collect the required data in real-time), will not take more that one man-hour and in most cases that activity should take no more than a few minutes. For code metrics collection purposes using Eclipse Metrics plugin, each of two releases need to be build locally, which include – downloading release from the remote repository, local build and XML metrics files collection. After measuring time spent on that activity, we found that it took no more than 2 man-hours.
Defect prediction preparation cost is the man-hour cost of defect prediction workflow preparation using the DePress tool. As generic workflows for most technologies used in the organization are pre-installed with the DePress tool, only correction actions are expected, if any. Results of time measurement say that preparation of a proper DePress workflow should not take more than one man-hour.
Summary of investment costs is presented in Table \ref{tab:costs-table}.