In Japan, university evaluation is compulsory, and many universities issue self-assessment reports yearly, often with the same table of contents. With this in mind, feature words from each chapter can extract for documents with nearly identical hierarchical structures. For example, by setting "table of contents" on the vertical axis and "fiscal year" on the horizontal axis and visualizing the feature words in a cross table, it is possible to find chronological changes in the feature words at a glance. This makes it possible to quickly grasp what has changed or not in each chapter. The present study looked at the chronological changes in Yamaguchi University's selfassessment documents from 2012 to 2016. With the developed system, we discovered a significant chronological change in Yamaguchi University's Diploma Policy, which is one of three policies. Yamaguchi University had already formulated and operated a similar policy called the Graduation Policy before the Diploma Policy became mandatory. The system showed that Yamaguchi University changed the "Graduation Policy" to "Diploma Policy" in line with the mandatory Diploma Policy. By using this system, even those who are not affiliated with Yamaguchi University have been able to grasp the significant changes in the past at the University. The reasons for any change in university policy should be explained to its stakeholders. The system can be an effective means for examining the decision-making process.