Effects of topic familiarity and search skills on query reformulation behavior

This study examined the effects of two factors, topic familiarity and search skills, on users' query reformulation behavior in health information searching. Four hypotheses were tested. Forty five graduate students participated in our study and searched for health-related topics on our experimental retrieval system. Their search actions were recorded by a server-side log system and their demographic information were collected, including their familiarity with the topics and their major. Our results suggest that topic familiarity and search skills do not have statistically significant impact on users' selection of query reformulation types. However, participants with a higher topic familiarity tend to make less spelling errors and prefer to use specific terms or search from different aspects. Participants with better searching skills are more likely to generalize and specify their queries and make less errors. In addition, significantly fewer reformulations were observed from the participants with higher topic familiarity. This indicates participants with higher topic familiarity can complete their task with less reformulation effort. There is no significant difference on the time spent on different types of query reformulations. The findings from this study yield practical implications for designing health information retrieval systems that support query reformulation for users with different knowledge and skills.