This paper describes the THISL system that participated in the TREC-7 evaluation, Spoken Document Retrieval (SDR) Track, and presents the results obtained, together with some analysis. The THISL system is based on the Abbot speech recognition system and the thislIR text retrieval system. In this evaluation we were concerned with investigating the suitability for SDR of a recognizer running at less than ten times realtime, the use of multiple transcriptions and word graphs, the effect of simple query expansion algorithms and the effect of varying standard IR parameters
