precision and recall
These two terms are used to describe the accuracy of resource retrieval.
The "precision" of resource retrieval refers to the relevancy of the results of a search.
The "recall" of resource retrieval refers to the number of relevant resources found by a search, out of the total number of relevant resources available.
The relationship between these two measures of retrieval accuracy is something of a trade-off, since improving one invariably causes problems with the other.
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