Abstract: The online deceptive reviews (ODRs)make great loss for the E-commerce ecosystem that includes online consumers, online merchants, and online platforms. Based on the motivation theory, the motivation and formation mechanism of ODRs are studied. On the one hand, we examine the motivation of consumers and merchants that may post deceptive reviews by using questionnaire survey.On the other hand, data analysis and structural equation model are combined to explore the formation mechanism of ODRs. Five types of motivations are investigated for posting ODRs with the two dimensions as consumer-related motivation and business-related motivation. A structural equation model is constructed to empirically examine the formation mechanism of ODRs. The findings of the paper are as follows. Firstly, the motivation of emotional catharsis, incentive mechanism, perfunctory response, and hiring “water army” is the direct motivation of posting ODRs. Secondly,the motivation of hiring “water army” has an indirect impact on the behavior of posting ODRs with the intermediary path of supporting or libeling merchants and promoting or defaming the merchants’ commodities. Thirdly, the “water army” post ODRs by promoting the merchants’ commodities and defaming the competitors’ commodities and, the underlying motivation of hiring “water army” is to boast the merchants and beat the competitors. The great managerial implications are provided to improve and optimize the ODRs management practice in the E-commerce platform and potential directions of effective governance and prevention of ODRs are provided.

Key words: E-commerce;online deceptive reviews; motivation theory; formation mechanism; structural equation model