An Evaluation Model of Credibility Calculation System for Natural Disasters Ken Honda a,1 and Naofumi Yoshida b a Graduate School of Global Media, Komazawa University, Japan b Faculty of Global Media Studies, Komazawa University, Japan Abstract. In this paper, an evaluation model of credibility calculation system is introduced. This system calculates information credibility by comparing target information with various reliable information resources on World Wide Web. The feature of the method is calculating information credibility by sensor data (earthquake, weather, railway sensors) besides primary sources (government, Ministry, press relation, supporting organization). The information credibility is calculated by degree of objectivity. Therefore, the system integrates high quality data from resources to derive objectivity. This paper presents a model of evaluation for credibility calculation system. The main contribution of this paper is to present evaluation model for credibility calculation system by recall and precision as a degree of false positive and false negative. And this paper shows the feasibility of the model by experiments of recall and precision for credibility calculation system. Keywords. Credibility, Objectivity, WWW, Sensor Data, Data Integration 1. Introduction Because of technological progress, information is flooding in modern society. In the situation, to secure information credibility is a critical issue. Especially, in emergency such as natural disasters, this issue becomes more important. In the Great East Japan Earthquake (March 11 th 2011), many types of rumor information were reported. Spreading rumor is caused various harms. For example, interrupting support of evacuations, wasting supplies and inspiring anxiety for disaster victims. According to these facts, the quality of information has to keep up high level. Thus, establishing a method for calculating information credibility is required. Spreading rumor is always occurred in the situation that collective tension is intensified. People who in the situation can not make calm judgment and behavior [6]. In the situation, people who collect information need to technological help. The system, which calculates information quality comprehensively and quantitatively, is required. There are a lot of studies about information credibility in the field of sociology and psychology. The research [1] analyzes the rumor and defines what is the rumor. This is the one of origin of researches about rumor. In the paper [8], rumor is analyzed from the point of view on computer technology. According to this paper, the credibility is not a property of an object, person or piece of information but is a perceive quality. In the paper [5], trust management techniques are categorized into four types. Those are 1 Ken Honda, E-mail: ken.h.0802@gmail.com