SP500215 Appendix A: TREC-2 Results Appendix National Institute of Standards and Technology D. K. Harman Box 4-- Fallout Level Averages lihes 1-11-- The average recall (probability of detection) at a fixed fallout (probability of false al&m rate). Ten equally spaeed fallout points in the high precislon end of the curve were used, and for each topic, the highest recall value in the region surrounding that fallout point is selected. The table shows the averages of these points across all topics. Graph 1-- Recall-Precision Curve This is a plot of the data shown in Box 2. Graph 2-- Fallout-Recall Curve This is a plot of the data shown in Box 4. Graph 3-- Normal Deviate - Fallout-Recall This is a plot of the data shown in Box 4, but plotted on probability scales. A-2