Experimental Components for the Evaluation of Interactive Information Retrieval Systems Pia Borlund Dawn Filan 3/30/04 610:551

The Goal To evaluate IR systems in a way that is as close to actual information seeking process as possible, while still being in a controlled environment.

Research Questions Can simulated information needs be substituted for real information needs? What makes a good simulated situation with reference to semantic openness and types of topics of the simulated situations?

Hybrid Evaluation Model Increased demand –Relevance revolution –Cognitive revolution –Interactive revolution Combine two main approaches –System-driven approach (controlled) –Cognitive user-centered approach (realism)

The Experimental Setting 3 components: The involvement of potential users as test persons The application of dynamic and individual information needs Use of dynamic relevance judgements

Ideal IIR Setting Real users who state personal information needs to the system and judge the relevance of the retrieved documents under controlled circumstances. Use of “simulated work task” Must be under controlled circumstances so that results can be compared across systems and user groups.

Simulated Work Task Triggers and develops a simulated information need by allowing for user interpretations of the situation. Platform against which situational relevance is measured. 2 variants applied: –Complete need applied (sim 1) –Only situation applied (sim 2)

Situational Relevance User-centered, realistic, and dynamic measure of relevance Judgements are not based on the request or query, but rather relate to the person’s requirements and mental state at the time of the retrieval Assessed continuously and interactively during the session

Relevance (Schamber, Eisenberg, and Nilan) Multidimensional cognitive concept whose meaning is dependant in users’ perceptions of information and their information needs Dynamic concept that depends on users’ judgements of quality of the relationship between information and the information need Complex but systematic and measurable concept if approached conceptually and operationally from the user’s perspective

Meta-Evaluation Should simulated work tasks be recommended as a component of the experimental setting for evaluating IIR systems?

Meta-Evaluation Questions Possibility of substituting real information needs with simulated information needs through the application of simulated work task situations. Whether the variants of the simulated task makes any difference to the test persons’ treatment of the information need What characterizes a good simulated work task in terms of how tailored the task should be to the user

Test Setting Full-text online system applying TREC data and probabilistic-based retrieval engine Search activity and relevance scores were logged 24 users from various academic backgrounds and education levels Asked to prepare a personal information need

Testing Procedure Brief questionnaire Introduction Explanation of the test person’s role Demo of the system Execution of 6 search tasks (training, real, 4 simulated tasks) Post-search interview

Conclusions One can substitute real information needs with simulated information through the application of simulated work tasks One can mix simulated and real information needs Treatment of the information need did not differ between the group that received the work task and request, and those who received just the work task.