As the volumes of software development increase and the cost reduction is required, most Japanese IT companies are interested in offshore software outsourcing. Although a lot of engineers have experienced the success and failure on their projects, their know-how still remains as tacit knowledge. This paper proposes a risk assessment scheme for new projects by externalizing such tacit knowledge. Such a scheme requires collaboration between industry and academia because the tacit knowledge is scattered over many companies and cannot be formalized by a single company or academic institute. Defining fourteen attributes related to software development and designing questionnaire about project evaluation, this paper clarifies how to quantify the risk of offshore software outsourcing. Risk assessment tool based on the proposed scheme will promote a knowledge spiral for project management.