IRS13
Scientific Report No. IRS-13 Information Storage and Retrieval
Evaluation Parameters
chapter
E. M. Keen
Harvard University
Gerard Salton
Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government.
11-3
r
Relevant Non Relevant
Examined a b a + b
Not Exa[OCRerr]ined C d C + d
a+c b+d a+b+c [OCRerr]d
I _________________________________________ ________________________________________ ______________________________________________________________ ______________________________________________
Recall = a a+b
Cut-off
a+c a+b+c+d
Precision = a (a+c)lOOO
Generality Number
a+b a+b+c+d
b
Fallout = b+d
The Retrieval Table that Results from Searching a System, with Five Ratios
Derived from the Table
Figure 1.