Exploring Composite Retrieval from the Users’ Perspective

Abstract

Aggregating results from heterogeneous sources and presenting them in a blended interface – aggregated search – has become standard practice for most commercial Web search engines. Composite retrieval is emerging as a new search paradigm, where users are presented with semantically aggregated information objects, called bundles, containing results originating from different verticals. In this paper we study composite retrieval from the user perspective. We conducted an exploratory user study where 40 participants were required to manually generate bundles that satisfy various information needs, using heterogeneous results retrieved by modern search engines. Our main objective was to analyse the contents and characteristics of user-generated bundles. Our results show that users generate bundles on common subtopics, centred around pivot documents, and that they favour bundles that are relevant, diverse and cohesive.