Patterns in information search for decision making: the effects of information abstraction

This paper reports on a study of abstraction in an information retrieval interface, where users had access to both detailed data and to two higher levels of abstraction of the data, in a multiple attribute alternative ranking situation. Through an experiment with a total of 76 subjects we found that, when they were not constrained by any built-in structure in their choice of information, there was a spectrum of use which combined various proportions of top-down search with opportunistic episodes (non-top-down branches to view various information attributes). We developed a measure of the degree of top-down search used, and found that this measure correlated positively with an increased propensity to use a compensatory decision strategy. Users also tended to reduce their use of top-down search in favour of more opportunistic search as they moved through the stages of the decision process. The degree of top-down search correlated significantly with a tendency to search within alternatives, but did not correlate with user domain experience. An implication of our findings is that, in order for a data retrieval interface to be implemented successfully, users should not be constrained by the system to follow a built-in search strategy, but should be allowed to develop their own search strategies through the use of a flexible interface.