A trust vector approach to transaction context-aware trust evaluation in e-commerce and e-service environments

At some e-commerce websites (such as eBay), a trust value of a seller is computed based on the ratings of past transactions given by buyers, which can only reflect the general or global trust level of a seller without any transaction context information taken into account. As a result, a buyer may be easily deceived by a malicious seller in a forthcoming transaction. For example, with the notorious value imbalance problem, a malicious seller can build up a high trust level by selling cheap products and then start to deceive buyers in selling expensive products. In this paper, we first model all contextual transaction factors that reflect the nature of transactions, and thus influence the evaluation of transaction trust. In addition, instead of providing a single trust value, we propose a trust vector approach that takes into account the contextual factors in transactions. Our model systematically categorize these factors into service aspect and transaction aspect. In particular, the computation of the elements in this trust vector is associated with both the context of past transactions and the context of a forthcoming transaction, so as to comprehensively indicate the trust level of a seller for the forthcoming transaction. The computed trust vector can be taken as the reputation profile of the seller. Empirical studies illustrate that it is important and necessary to introduce contextual transaction factors in evaluating the trust level of sellers objectively.