Has adhoc retrieval improved since 1994?

Evaluation forums such as TREC allow systematic measurement and comparison of information retrieval techniques. The goal is consistent improvement, based on reliable comparison of the effectiveness of different approaches and systems. In this paper we report experiments to determine whether this goal has been achieved. We ran five publicly available search systems, in a total of seventeen different configurations, against nine TREC adhoc-style collections, spanning 1994 to 2005. These runsets were then used as a benchmark for reassessing the relative effectiveness of the original TREC runs for those collections. Surprisingly, there appears to have been no overall improvement in effectiveness for either median or top-end TREC submissions, even after allowing for several possible confounds. We therefore question whether the effectiveness of adhoc information retrieval has improved over the past decade and a half.