ntpp.default: An S3 Method to Compute the Ratio of Total Tests to Positive...

In sgutreuter/screenr: Construction of Binary Test-Screening Rules

An S3 Method to Compute the Ratio of Total Tests to Positive Results

Description

ntpp.default computes the ratio of the total number of tests performed per positive test result and the anticipated proportion of the untested (those screened out of testing) who would actually test positive.

Usage

## Default S3 method:
ntpp(object = NULL, ..., se = NULL, sp = NULL, prev = NULL)

Arguments

object	unused, specify se, sp and prev
...	optional arguments to ntpp methods.
se	a numeric vector of sensitivities in (0,1)
sp	a numeric vector of sensitivities in (0,1)
prev	a numeric vector of positive proportions of the testing condition, in (0,1)

Details

The anticipated number of tests required to detect a single positive nntp is given by

nntp = (SeP + (1 - Sp)(1 - P)) / SeP

where Se is sensitivity, P is prevalence and Sp is specificity. The anticipated positive proportion among those screened out is given by

Puntested = ((1 - Se)P) / ((1 - Se)P + Sp (1 - P))

Value

ntpp.default returns a data frame containing the following columns:

sensitivity

the sensitivity (proportion)

specificity

the specificity (proportion)

prev

positivity proportion of the test condition

ntpp

anticipated total tests required per positive result

prev_untested

anticipated positive proportion among the untested

sgutreuter/screenr documentation built on Nov. 20, 2022, 2:41 a.m.