Siemens TREC-4 Report: Further Experiments with Database Merging

A database merging technique is a strategy for combining the results of multiple, independent searches into a single cohesive response. An isolated database merging technique selects the number of documents to be retrieved from each database without using data from the component databases at run-time. In this paper we investigate the eeectiveness of two isolated database merging techniques in the context of the TREC-4 database merging task. The results show that on average a merged result contains about 1 fewer relevant document per query than a comparable single collection run when retrieving up to 100 documents.