Thursday, September 4, 2008

Question on homework - Plotting precision/recall curve

There was  a question regarding the homework:


“Clarification on #2: Are we supposed to plot the precision and recall numbers after each document is fetched in the query? My interpretation of the initial formulation seems to yield only 1 point, which is a bit nonsensical for plotting a curve...”


The answer is yes you should plot the precision/recall after each relevant document is fetched.  In the slides the frequently used 11-point precision/recall curve is shown…This is done by interpolating and finding each of the eleven points…If you plot the curve for each document (relevant or not) and don’t interpolate, you often times end up with a saw tooth shaped curve…




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