The Effects of Incomplete Information on Consumer Choice

Two current trends, information overload and marketers' increased control over the manner in which their products are sold and presented to buyers (e.g., on the Internet), 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, researchers still know little about the effect of missing information on consumer choice. Building on prior work by Slovic and MacPhillamy (1974), the authors demonstrate that a tendency to give more weight to attributes on which all considered options have values (common attributes), compared with attributes for which not all options have values (unique attributes), can often lead to intransitive preferences. Using process measures, the authors further show 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 missing values cannot account for the observed effects of missing information on consumer choice. The authors also show that the purchase decisions of buyers who consider attribute importance before 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 affect buyer tastes and purchase decisions made subsequently. The authors discuss the theoretical and practical implications of this research.