19 Oct 2004
CS 5244: Library Evaluation
28
Factoring in size of a corpus
¡Look at how P/R or Sn/Sp varies as a function of rank:
¡Choose a number of different ranks and calculate P/R or Sn/Sp
lCorrespond to vertical lines on graphs at right
lPlot Sn vs. 1-Sp to get points for ROC curve.
Interpolate curve.
Irrelevant
Relevant
Rank
n
1
Relevant
Irrelevant
Which of these
examples is
which from the previous slide?
which from the previous slide?
