Previous studies showed that using assurance cases to increase the feasibility of accomplishing management vision and management strategy. The assurance case description method proposed by previous studies, however, does not take into account the work whose purpose changes in the progress. This study proposes an assurance case description method according to the PROCESS definition defined in this study, for being able to visualize that assuring a task whose purpose changes according to the work progress. The reason we refer to ISO 15288:2015 is that PROCESS defined in ISO 15288:2015 considers Purpose, and thus assumes changes in a certain work's purpose in the progress of the work. This study evaluates the effectiveness of both a) being able to understand the purpose of PROCESS and b) being able to visualize that assuring a work whose purpose changes according to the work progress by using both open coding and paired t-test. Based on the paired t-test result, the proposed description method was judged effective compared with current practice, about a) being able to understand the purpose of PROCESS and b) being able to visualize that assuring a work whose purpose changes according to the work progress. Furthermore, from the open coding results, the results suggested why the proposed description method is effective. This study concludes with future research topics.
