Precision and Recall
Precision and recall. These terms are bandied about in most every discussion about search. What do they really mean and how do we evaluate them? To those of us immersed in the thick of search lore, we have lots of answers but we certainly don’t make them easy to understand to the uninitiated. There is quite a large wall around our little garden. In this article, we hope to demystify the discussion a bit by focusing on the tradeoff that is inherent between the two concepts in context of how it applies to real world examples. |
In the realm of information access and search, precision and recall are the logic for determining the order in which results are returned for a query and how many of them should appear (the threshold). The logic amounts to a series of detection problems, for example, finding the correct spelling of a term in a query, deciding whether audio is noise or speech, determining if a noun phrase is worthy of being a navigator for exploration, or calculating a sentiment score on a document.