|all Thesa topics
|map of the Thesa web site
Recall is the ratio of relevant retrievals to relevant items. Precision is the ratio of relevant items to retrieved items. If a search yields a high precision ratio, it typically has a low recall ratio. The problem worsens as the size of the document collection increases. The classic paper is Blair and Maron's 1985 study of the STAIRS document-retrieval system with 350,000 pages (QuoteRef: blaiDC3_1985 ). They demonstrated that the lawyers who built the collection retrieved less that 20 percent of the relevant documents.
Thesa avoids the tradeoff between recall and precision by a directed search for relevant material. The user locates a relevant topic via keywords, and searches the neighborhood of that topic for other relevant topics. Descriptive titles make a directed search practical because the user culls titles that do not appear relevant. Related topics make directed search exhaustive because every topic is near every other topic.
|ThesaHelp: a preliminary test of directed search
|ThesaHelp: how to find everything relevant to some topic or question
|ThesaHelp: needle-in-a-haystack test of directed search
|ThesaHelp: read-everything test of directed search
|Topic: information retrieval by following links
|Topic: information retrieval by relevance
|Topic: information retrieval by searching