An R package to enable screening in/out subjects who are likely to to test positive/negative, respectively.
Consider the situation where a definitive test for some condition is expensive, and the condition is rare. In that case, universal testing would not be efficient in terms of the yield of postive results per test performed. Now suppose that responses to a set of simple diagnostic questions or observations may be predictive of the definitive test result. Package screenr enables the estimation of thresholds for making decisions about when to perform the definitive test on newly observed subjects based on Receiver Operating Characteristics (ROC) estimated from an initial sample. The choice of a particular screening threshold is left to the user, and should be based on careful consideration of application-specific tradeoffs between sensitivity (true positive fraction) and specificity (true negative fraction).
Open an R session and do:
# install.packages("devtools")
devtools::install_github("sgutreuter/screenr", build_vignettes = TRUE,
build_manual = TRUE)or
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Browse to https://github.com/sgutreuter/screenr.
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Click on the Code pull-button near the upper-right corner, select Download ZIP and save the zip archive in a location of your choice.
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Unzip the archive into a directory named screenr.
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Open a shell/terminal in the directory containing the unzipped screenr directory.
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Execute ‘R CMD INSTALL ./screenr’
The tutorial is recommended for first-time users:
library(screenr)
vignette("screenr_Tutorial", package = "screenr")