A geometric interpretation of r-precision and its correlation with average precision

We consider two of the most commonly cited measures of retrieval performance: average precision and R-precision. It is well known that average precision and R-precision are highly correlated and similarly robust measures of performance, though the reasons for this are not entirely clear. In this paper, we give a geometric argument which shows that under a very reasonable set of assumptions, average precision and R-precision both approximate the area under the precision-recall curve, thus explaining their high correlation. We further demonstrate through the use of TREC data that the similarity or difference between average precision and R-precision is largely governed by the adherence to, or violation of, these reasonable assumptions. Categories and Subject Descriptors H.3.4 [Information Storage and Retrieval]: Systems and Software – Performance evaluation General Terms Theory, Measurement, Experimentation Keywords Average Precision, R-precision, Precision-recall Curve

• Type: Conference
• Year: 2005
• Where: SIGIR
• Authors: Javed A. Aslam, Emine Yilmaz, Virgiliu Pavlu
• Keywords: Average Precision, Commonly Cited Measures, Precision-recall Curve, SIGIR 2005