SP500215 Description of the PRC CEO Algorithm for TREC-2 chapter P. Thompson National Institute of Standards and Technology D. K. Harman our summary official TREC-2 results for versions 1 and 2 respectively. Queryid (Num): all prceol Total number of documents over all queries Retrieved: 50000 Relevant: 10785 Rel_ret: 3561 Interpolated Recall - Precision Averages: at 0.00 0.4768 at 0.10 0.2613 at 0.20 0.1807 at 0.30 0.1202 at 0.40 0.0875 at 0.50 0.0504 at 0.60 0.0328 at 0.70 0.0169 at 0.80 0.0142 at 0.90 0.0077 at 1.00 0.0031 Average precision (non-interpolated) over all rel does 0.0904 Precision: At S docs: 0.2120 At 10 docs: 0.2480 At 15 docs: 0.2707 At 20 docs: 0.2760 At 30 docs: 0.2753 At 100 docs: 0.2418 At 200 docs: 0.1756 At 500 does: 0.1086 At 1000 docs: 0.0712 R-Precision (precision after a query) docs retrieved): Exact: 0.1703 R(=num_relfor Queryid (Num): Total number of Retrieved: Relevant: Rel_ret: Interpolated at 0.00 at 0.10 at 0.20 at 0.30 at 0.40 at 0.50 at 0.60 at 0.70 at 0.80 at 0.90 at 1.00 Average precision rel docs all prceol documents over all queries 50000 10785 3323 Recall - Precision Averages: 0.5963 0.3270 0.2306 0.1430 0.0866 0.0425 0.0323 0.0246 0.0209 0.0131 0.0041 (non-interpolated) over all 0.1120 Precision: At S docs: 0.4120 At 10 docs: 0.4000 At 15 docs: 0.3920 At 20 docs: 0.3740 At 30 docs: 0.3527 At 100 docs: 0.2722 At 200docs: 0.1974 At SOodocs: 0.1090 At 1000 docs: 0.0665 R-Precision (precision after R (= numjel for a query) docs retrieved): Exact: 0.1809 Figure 1: Summary scores 1 using two best experts for PRC version Figure 2: Summary scores for PRC version 2 using five best experts 273