Contents I. Introduction
Daily news and analyst reports have the potential to influence economic indicators such as product sales and stock prices [1] – [4] . Therefore, assessing opinions in the market by analyzing such news and reports is recognized as an important task in economic activities such as trading and marketing. At the same time, we have general or unique knowledge of the causal or influence relationships among events, even in a vague way, and our evaluations of the validity of our opinions and hypotheses are often based on evaluations of other hypotheses that are causally related. Therefore, when evaluating our own hypotheses and opinions, it is important to consider these causal relationships in addition to the reputation of the market, which consists of reports and news. In fact, many analysts spend a considerable amount of time on this kind of task, i.e., reading news and reports and evaluating various opinions or hypotheses by considering their own, or commonly assumed, knowledge of the influence of events.
