Acknowledgements

Thanks to Stephen Robertson and Stephen Walker for making
OKAPI available to UCLA.

  We are especially thankful to Stephen Walker for all his con-
tinuing help over and above that indicated in the text.

  We wish to thank Donna Harman of NIST for her support
during TREC-2.

  This research was supported by a UCLA Academic Senate
grant that also provided financial support for the graduate re-
search assistantship of PVB.

  Finally, ENE is grateful to SUN Microsystems Inc. for the
equipment grant of the SPARC 2 that made this research p05-
sible.


References
Efthimiadis, E.N. (1993a) A user-centered evaluation of rank-
  ing algorithms for interactive query expansion. In: Korfhage
  R., Rasmussen E. and Willett P. (eds.) Proceedings of the
  16th International Conference of the Association of Comput-
  ing Machinery, Specialist Interest Group in Information Re-
  trieval, June 1993. Pittsburgh, PA: ACM Press. pp.146-159.
Efthimiadis, E.N. (in press) `User choices: As the yardstick for
  the evaluation of ranking algorithms for interactive query ex-
  pansion.' Information Processing ~ Management. In press.
Efthimiadis, E.N. `Interactive Query Expansion:   A User-
  based evaluation in a Relevance Feedback Environment.'
  Manuscript submitted for publication.
Harper, D.J. & van Rijsbergen, C.J. (1978) An evaluation
  of feedback in document retrieval using co-occurrence data.
  Journal of Documentation, 34(3), 189-216.
Porter, M.F. & Galpin, V. (1988) Relevance feedback in a public
  access catalogue for a research library: Muscat at the Scott
  Polar Research Institute. Program, 22(1), 1-20.
Robertson, S.E. (1990) On term selection for query expansion.
  Journal of Documentation, 46(4), 359-364.
Robertson, S.E. and Sparck Jones, K. (1976) Relevance weight-
  ing of search terms. Journal of the American Society for In-
  formation Science, 27(3), 129-146.
Robertson, S.E., Walker, S., Hancock-Beaulieu, M., Gull, A. &
  Lau, M. (1993a) Okapi at TREC. In: Harman, D. K. (Ed.)
  The First Text Retrieval Conference (TREC-1). Proceedings.
  NIST Special Publication 500-207. Gaithersburg, MD: NIST,
  1993. pp2l-30.
Robertson, S.E., Walker, S., Jones, S., Hancock-Beaulieu, M.,
  & Gatford, M. (1993b) Okapi at TREC-2. In: Harman, D.K.
  (Ed.) Text Retrieval Conference (TREC-2). Galthersburg,
  MD: NIST, August 30-September 1, 1993, Proceedings, to
  appear.


                                                      289

van Rusbergen, C.J. (1977) A theoretical basis for the use of
  co-occurrence data in information retrieval. Journal of Doc-
  umentation, 33, 106-119.
van Rijsbergen, C.J., Harper, D.J. & Porter, M.F. (1981) The
  selection of good search terms. Information Processing and
  Management, 17(2), 77-91.


A    Runs

The runs presented here are grouped by algorithm used for the
expansion. The list starts with runs that did not include query
expansion.

  bmlS.phn.qen.uclagsln
bmlS.phn.qen.uclagsly
bmlS.phy.qen.uclagsly
bmlS.phb.qen.uclagsly

bmlS.phb.qey:wpq-10-5.uclagsln
bmlS.phb.qey:wpq-10-5.uclagsly
bmlS.phb.qey:wpq-10-10.uclagsln
bmlS.phb.qey:wpq-10-10.uclagsly
bmlS.phb.qey:wpq-10-15.uclagsln
bmlS.phb.qey:wpq-20-5.uclagsln
bmlS.phb.qey:wpq-20-10.uclagsln
bmls.phb.qey:wpq-20-15.uclagsln
bmlS.phb.qey:wpq-30-5.uclagsln
bmlS.phb.qey:wpq-30-10.uclagsln
bmlS.phb.qey:wpq-30-15.uclagsln

bmlS.phb.qey:emim-10-10.uclagsln
bmlS.phb.qey:emim-10-10.uclagsly
bmlS.phb.qey:emim-20-10.uclagsly
bmlS.phb.qey:emim-30-10.uclagsly

bmlS.phb.qey:port-10-10.uclagsln
bmlS.phb.qey:port-10-10.uclagsly
bmlS.phb.qey:port-20-10.uclagsly
bmlS.phb.qey:port-30-10.uclagsly

bm15.phb.qey:r~hi1o-10-10.uclagsln
bm15.phb.qey:r~hilo-10-10.uclagsly

bmlS.phb.qey r lohi 10 5.uclagsln
bmlS.phb.qey r lohi 10 10.uclagsln
bmlS.phb.qey r lohi 10 10.uclagsly
bmlS.phb.qey r lohi 10 15.uclagsln
bmlS.phb.qey r lohi 20 5.uclagslu
bmlS.phb.qey r lohi 20 l0.uclagsln
bmlS.phb.qey.rAohi 20 15.uclagsln
bmlS.phb.qey:rAohi-30-5.uclagsln
bmlS.phb.qey:rAohi-30-10.uclagsln
bm15.phb.qey:r~lohi-30-15.uclagsln