Known-Item Search Success
Known-item search is the case where the user is looking for one specific document they already know exists — a particular paper, book, web page, or record — rather than exploring a topic. Evaluation is correspondingly specialized: with exactly one correct answer per query, the question is simply how high the system ranks that single target. The natural measures are reciprocal rank (and its mean, MRR), success-at-k, and Cooper's expected search length, which counts how many wrong documents the user must wade through before reaching the right one. These metrics, averaged over many known-item topics, give a clean, interpretable picture of how well a system supports re-finding a specific document.
Source record
Citations copied verbatim from the method’s source record. No claim-level verification is inferred from them.
- Cooper, W. S. (1968). Expected search length: A single measure of retrieval effectiveness based on the weak ordering action of retrieval systems. American Documentation, 19(1), 30-41. · DOI 10.1002/asi.5090190108
- Manning, C. D., Raghavan, P., & Schütze, H. (2008). Introduction to Information Retrieval. Cambridge University Press. · ISBN 9780521865715
- Voorhees, E. M., & Harman, D. K. (Eds.). (2005). TREC: Experiment and Evaluation in Information Retrieval. MIT Press. · ISBN 9780262220736
Curated claims
Claims persisted in the evidence ledger, each with its own assessment.
This view does not invent a claim assessment when the ledger has none.
Related methods
Generated from the method graph and shown as machine-suggested relations — no evidence claim is inferred.