Reference Work Entry

Encyclopedia of Database Systems

pp 2453-2453

R-Precision

  • Nick CraswellAffiliated withMicrosoft Research Cambridge

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 \({r}\over{R}\).

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 \({r}\over{R}\).

Cross-references

Average R-Precision

Precision

Precision at n

Precision-Oriented Effectiveness Measures

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