|all Thesa topics
|map of the Thesa web site
Use the needle-in-a-haystack test to estimate recall and precision for large collections. In a large collection, an exhaustive search is impractical, making recall and precision difficult to measure.
- Have someone select random quotations in Thesa, and write questions which the quotations help answer. The question should not use keywords from the quotation.
- Ask a subject to locate all material relevant to the question.
- If the subject does not select the quotation, ask whether it is relevant and if not, why not.
- Repeat this procedure to estimate the recall and precision ratios. If subject looks at 200 items, identifies 70 relevant items, and locates 90% of the selected quotations, the recall is 0.90 and the precision is 0.35.
- You may use the same procedure, to test keyword searching.
|ThesaHelp: a preliminary test of directed search
|ThesaHelp: read-everything test of directed search
|Topic: information retrieval by searching