Abstract: The credibility assessment of network health information is a complex problem proposed recently, which can be considered from the perspective of multidimensional information characteristics according to the existing theories. This paper aims to establish a credibility evaluation index system of network health information, which can be used to evaluate and filter the network health information for search engines, and also provide guidance and suggestions of credibility evaluation to information users.According to the connotation of information credibility, this paper puts forward three dimensions of information content, information source and communication media, designs the evaluation index system of network health information credibility, determines the index weight through analytic hierarchy process, and uses natural language processing technology and assignment transformation to measure indexes automatically. Disease prevention, disease symptoms and disease treatment, these three typical themes in the context of Internet health information search are considered in empirical research. Comparing the system score with the ‘Gold Standard’ labeled by the two experts, the credibility evaluation index system is proved effectively to evaluate the credibility of network health information. Under the credibility dichotomy, the evaluation accuracy and precision ratio reached more than 90%, and the scoring threshold interval of credibility under five classifications is wide at both ends and narrow in the middle, which could effectively distinguish the trusted and untrusted network health information.

Key words: Information credibility, Network health information, Information characteristics, Assessment index