Please note: This PhD defence will be given online.
Mustafa Abualsaud, PhD candidate
David R. Cheriton School of Computer Science
Supervisor: Professor Mark Smucker
After a user submits a query and receives a list of search results, the user may abandon their query without clicking on any of the search results. A bad query abandonment is when a searcher abandons the SERP because they were dissatisfied with the quality of the search results, often making the user reformulate their query in the hope of receiving better search results. As we move closer to understanding when and what causes a user to abandon their query under different qualities of search results, we move forward in an overall understanding of user behavior with search engines. In this thesis, we describe three user studies to investigate bad query abandonment.
First, we report on a study to investigate the rate and time at which users abandon their queries at different levels of search quality. We had users search for answers to questions, but showed users manipulated SERPs that contain one relevant document placed at different ranks. We show that as the quality of search results decreases, the probability of abandonment increases, and that users quickly decide to abandon their queries. Users make their decisions fast, but not all users are the same. We show that there appear to be two types of users that behave differently, with one group more likely to abandon their query and are quicker in finding answers than the group less likely to abandon their query.
Second, we describe an eye-tracking experiment that focuses on understanding possible causes of users’ willingness to examine SERPs and what motivates users to continue or discontinue their examination. Using eye-tracking data, we found that a user deciding to abandon a query is best understood by the user’s examination pattern not including a relevant search result. If a user sees a relevant result, they are very likely to click it. However, users’ examination of results are different and may be influenced by other factors. The key factors we found are the rank of search results, the user type, and the query quality. For example, we show that regardless of where the relevant document is placed in the SERP, the type of query submitted affects examination, and if a user enters an ambiguous query, they are likely to examine fewer results.
Third, we show how the nature of non-relevant material affects users’ willingness to further explore a ranked list of search results. We constructed and showed participants manipulated SERPs with different types of non-relevant documents. We found that user examination of search results and time to query abandonment is influenced by the coherence and type of non-relevant documents included in the SERP. For SERPs coherent on off-topic results, users spend the least amount of time before abandoning and are less likely to request to view more results. The time they spend increases as the SERP quality improves, and users are more likely to request to view more results when the SERP contains diversified non-relevant results on multiple subtopics.
To join this PhD defence on Zoom, please go to https://uwaterloo.zoom.us/j/93498366790?pwd=RWllT0pPd25GbC9yL1h4OTl6TUJudz09.
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