  In electronic commerce (e-commerce)markets, a decision-maker faces a
sequential choice problem. Third-party intervention plays an important role in
making purchase decisions in this choice process. For instance, while
purchasing products/services online, a buyer's choice or behavior is often
affected by the overall reviewers' ratings, feedback, etc. Moreover, the
reviewer is also a decision-maker. After purchase, the decision-maker would put
forth their reviews for the product, online. Such reviews would affect the
purchase decision of another potential buyer, who would read the reviews before
conforming to his/her final purchase. The question that arises is \textit{how
trustworthy are these review reports and ratings?} The trustworthiness of these
review reports and ratings is based on whether the reviewer is a rational or an
irrational person. Indexing the reviewer's rationality could be a way to
quantify a reviewer's rationality but it does not communicate the history of
his/her behavior. In this article, the researcher aims at formally deriving a
rationality pattern function and thereby, the degree of rationality of the
decision-maker or the reviewer in the sequential choice problem in the
e-commerce markets. Applying such a rationality pattern function could make it
easier to quantify the rational behavior of an agent who participates in the
digital markets. This, in turn, is expected to minimize the information
asymmetry within the decision-making process and identify the paid reviewers or
manipulative reviews.
