The defenitions for FPIR, SEL, FNIR for an identification problem are as follows, but they look complicated for me. (specially using Rank and L candidates concept in computation).
Specially the concept of selectivity is complicated for me!
can any one explain them by a simple identification example?
FPIR (N,T,L)=(Num. nonmate searches where one or more enrolled candidates are returned at or above threshold, T)/(Num. nonmate searches attempted)
SEL(N,T,L)=(Num. nonmate enrolled candidates returned at or above threshold, T)/(Num. nonmate searches attempted)
FNIR(N,R,T,L)=(Num. mate searches with enrolled mate found outside top R ranks or score below threshold, T)/(Num. mate searches attempted)
The following are simple definitions for FPIR and FNIR:
A threshold "T" is used to classify a test case to be either a correct (true or positive) case or false (negative) case. If the case is below a threshold "T" then it is classified false (negative) and if it is above threshold "T" it is classified true (positive).
FPIR: is the false positive identification rate. It is the ratio of the test cases that are classified as true cases although they are false cases. It is type I error.
FPIR= Number of test cases classified above threshold "T" (true) / Number of all test cases
FNIR: is the false negative identification rate. It is the ratio of the test cases that are classified as false cases although they are true cases. It is type II error.
FNIR= Number of test cases classified below threshold "T" (false) / Number of all test cases
Dear Bahare Moradi,
Look the links, please.
http://www.csee.wvu.edu/~gdguo/courses/fa13/biom426/Slides/Lecture6.pdf
http://biometrics.nist.gov/cs_links/iris/irexIV/IREX_IV_conops_v03.pdf
Regards, Shafagat
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