pv.gs {DTComPair}

Generalized Score Statistic for Comparison of Predictive Values

Description

Performs a test for differences in (positive and negative) predictive values of two binary diagnostic tests using a generalized score statistic proposed by Leisenring, Alonzo and Pepe (2000).

Usage

pv.gs(tab)

Arguments

tab

An object of class tab.paired.

Value

A list containing:

ppv

A list with test1 (the positive predictive value of test 1), test2 (the positive predictive value of test 2), diff (the difference in positive predictive values, computed as test2 - test1), the test.statistic and the corresponding p.value.

npv

A list with test1 (the negative predictive value of test 1), test2 (the negative predictive value of test 2), diff (the difference in negative predictive values, computed as test2 - test1), the test.statistic and the corresponding p.value.

method

The name of the method used to compare predictive values, here “generalized score statistic (gs)”.

References

Leisenring, W., Alonzo, T., and Pepe, M. S. (2000). Comparisons of predictive values of binary medical diagnostic tests for paired designs. Biometrics, 56(2):345-51.

See Also

pv.wgs and pv.rpv.

Examples

data(Paired1) # Hypothetical study data
ftable(Paired1)
paired.layout <- tab.paired(d=d, y1=y1, y2=y2, data=Paired1)
paired.layout 
gs.results <- pv.gs(paired.layout)
str(gs.results)
gs.results
gs.results$ppv["p.value"]