Overview: Okapi at TREC
TREC (Text REtrieval Conference) is a large scale experiment involving a number
of research groups working on text retrieval. Each participating team takes on
the same three gigabytes of text data and the same set of fifty search requests
, and runs them through its own system. Output is sent to the US National
Institute of Standards and Technology (NIST) for assessment, and a number of
performance measures are calculated. These measures are not independent, but
focus on the ability of the system to find items which the assessors regard as
relevant. Thus they attempt to measure effectiveness in a user-oriented sense,
rather than efficiency in time or cost.