In civil disputes, the parties can reach resolution by any of the following four means: litigation, negotiation, mediation, and arbitration. The last three are known as Alternative Dispute Resolution (ADR) among which negotiation is the most common way of resolution. When deciding the resolution method, the parties will first analyze possible gain and loss that can be incurred from each method. This decision making process is known as "Case Valuation". Conventional rational choice theory has explained the process of case valuation based on the premise that the parties will make rational choice. However, based on its recent findings, contemporary cognitive psychology challenges the rationality premise and argues that human behavior during case valuation may not be rational. This study first reviews decision-making process based on rational choice theory, then considers various factors that may interfere with rational decision-making process. Lastly, the study debates whether a decision-making model based on rational choice theory can no longer serve as a reliable and accurate model to explain the decisions made by the parties during case valuation.