On Topic Difficulty in IR Evaluation
Fabio Zampieri, Kevin Roitero, J. Shane Culpepper, Oren Kurland, Stefano Mizzaro · 2019
In a test collection setting, topic difficulty can be defined as the average effectiveness of a set of systems for a topic. In this paper we study the effects on the topic difficulty of: (i) the set of retrieval systems; (ii) the underlying document corpus; and (iii) the system components. By generalizing methods recently proposed to study system component factor analysis, we perform a comprehensive analysis on topic difficulty and the relative effects of systems, corpora, and component interactions. Our findings show that corpora have the most significant effect on topic difficulty.