Definition
For a given query topic Q, R-precision is the precision at R, where R is the number of relevant documents for Q. In other words, if there are r relevant documents among the top-R retrieved documents, then R-precision is \( \frac{r}{R} \).
Key Points
R-precision is defined as the proportion of the top-R retrieved documents that are relevant, where R is the number of relevant documents for the current query. This requires full knowledge of a query’s relevant set, and will be a shallow evaluation for a query with few relevant documents and a deep evaluation for a query with many relevant documents. Rank cutoff R is the point at which precision and recall are equal, since at that point both are \( \frac{r}{R} \).
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Craswell, N. (2018). R-Precision. In: Liu, L., Özsu, M.T. (eds) Encyclopedia of Database Systems. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-8265-9_486
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DOI: https://doi.org/10.1007/978-1-4614-8265-9_486
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