Having analyzed the results of projects concluded successfully in the last several years, we have shown project management processes as quantitative data. Using those data, we have created a guideline for customizing the project management processes. We have found out effectiveness of the guideline by applying it to a couple of pilot projects. The projects applied an iterative approach. Through the success of the pilot projects, we have also discovered that the past data of a waterfall development style project can be used as analysis input for an iterative development project.