Recall measures the quantity of results returned by a search and precision is the measure of the quality of the results returned. Recall is the ratio of relevant results returned divided by all relevant results. Precision is the number of relevant results returned divided by the total number of results returned.
The diagram represents a low-precision, low-recall search. The red and green dots represent the total population of potential search results for a given search. Red dots represent irrelevant results, and green dots represent relevant results. Relevancy is indicated by the proximity of search results to the center of the inner circle. Of all possible results shown, those that were actually returned by the search are shown on a light-blue background. In the example only one relevant result of three possible relevant results was returned, so the recall is a very low ratio of 1/3. The precision for the example is a very low 1/4, since only one of the four results returned was relevant.
"Pro Full-Text Search in SQL Server 2008 (Expert's Voice in SQL Server)"
ReplyDeleteby Michael Coles and Hillary Cotter
Returned results could be relevant or irrelevant?
ReplyDeletefull-text searching alone may be sufficient, and that *metadata searching as a surrogate is not necessary.
(in a sense maybe yes, maybe no.* when going to supermaket/department store, if one know what want, one don't need metadata ad as sales guide, one go direct to the source(full text) and find/pick items. for others who has limited time not familiar with supermarket/department setting, or just wish if something maybe fit the needs and budget, one will want to look the metadata ad to decide if further shopping/search are necessary or not.)
*link anchor text, which can be regarded as metadata created by others, is much more effective in identifying best answers to queries than other textual evidence.
with the possiblity of bookmark/indexing the metadata within each full-text document, metadata alone as a surrogate is then not necessary*.
* each metadata info alone can be rearranged and attached to each full-text as
1. bookmarked info.
2. context pages maybe created such as metadata for agendas. could also link/match to its full-text front page when full-text of its e-series created.
search engine itself is a powerful indexing/sorting system that provides grouped/ sorted relevant indexing(titles/subjects) info to the searchers.
ReplyDeletehow to make each company's information relevant to which larger data group and how to avoid irrelevant group is the contribute key to company's success.