The impact of corpus size on question answering performance
Charles L. A. Clarke, Gordon V. Cormack, Michael J. Laszlo, Thomas R. Lynam, Egidio L. Terra · 2002
Using our question answering system, questions from the TREC 2001 evaluation were executed over a series of Web data collections, with the sizes of the collections increasing from 25 gigabytes up to nearly a terabyte.