The primary objective of this research is to investigate the impact of case-based decision support systems on decision makers' certainty in their selection when using case-based decision support systems for accounting choices emphasizing depreciation methods. Two case-based decision support systems (a plain case-based decision support system and a traditional case-based decision support system) were developed. A laboratory experiment was performed with one hundred and four graduate students studying for a Master's degree in accounting. The results suggested that the effects of asymmetries in the distribution of information and in information processing on certainty in decision making was significant for a traditional case-based decision support system. However, the decision makers' perceived value of information moderated the relationship between asymmetries in the processing of information and certainty in decision making.