Measuring task complexity in information search from user's perspective

Task complexity is a critical task characteristic that influences users' information seeking and search behavior. In general, researchers differentiate task complexity from objective and subjective task complexity. Both significantly affect task performance. However, few studies have been done to examine how task complexity could be measured from users' perspective in information science. The present study identifies a set of objective and subjective measures and conducted a survey. The survey asked users to judge the complexity of a task, and then give the reasons why they made that judgment based on the measures. Six simulated task situations were developed for the survey and 168 valid questionnaires (84% return rate) were analyzed. The results indicate that the number of words hard to understand, the number of languages required for search results, and the number of domain areas involved in a task could significantly predict task complexity. The study helps further understand the attributes of task complexity and has implications in research on interactive information retrieval (IIR), task-based information seeking and search, and personalization of information retrieval (IR).