The Effects of Incomplete Information on Consumer Choice

Two current trends, information overload combined with increased control of marketers (e.g., on the Internet) over the manner in which their products are sold and presented to buyers, suggest that deciding what information to provide or not to provide can determine a product's success in the marketplace. Although it has long been recognized that most purchase decisions are made with incomplete information, we still know very little about the effect of missing information on consumer choice. Building on earlier work by Slovic and MacPhillamy (1974), we demonstrate that a tendency to give more weight to attributes on which all considered options have values ("common attributes"), relative to attributes for which not all options have values ("unique attributes"), can often lead to intransitive preferences. Using process measures, it is further shown that buyers tend to interpret missing attribute values in a way that supports the purchase of the option that is superior on the common attribute. The results indicate that information presentation format and inferences about mission values cannot account for the observed effects of missing information on consumer choice. We also show that the purchase decisions of buyers who consider attribute importance prior to making a choice and those with high need for cognition are less susceptible to influence by missing information. Finally, the findings indicate that choosing from sets with missing information can impact buyer tastes and purchase decisions made subsequently. We discuss the theoretical and practical implications of this research.