  The objective of this research was to find out how the two search engines
Google and Bing perform when users work freely on pre-defined tasks, and judge
the relevance of the results immediately after finishing their search session.
In a user study, 64 participants conducted two search tasks each, and then
judged the results on the following: (1) The quality of the results they
selected in their search sessions, (2) The quality of the results they were
presented with in their search sessions (but which they did not click on), (3)
The quality of the results from the competing search engine for their queries
(which they did not see in their search session). We found that users heavily
relied on Google, that Google produced more relevant results than Bing, that
users were well able to select relevant results from the results lists, and
that users judged the relevance of results lower when they regarded a task as
difficult and did not find the correct information.
