Calculates the Positive likelihood ratio

This function calculate the Positive Likelihood Ratio estimator, their standard error estimated and a confidence interval in a traverse or Cross-sectional study.

Usage

ebdt_plr(s1, r1, s0, r0, conflev = 0.95, digits = 3)

Arguments

s1: Non-negative numeric. TP - True positive (cases correctly classified as +).
r1: Non-negative numeric. FP - False positives (controls classified as +).
s0: Non-negative numeric. FN - False negatives (cases classified as -).
r0: Non-negative numeric. TN - True negatives (controls classified as -).
conflev: Confidence level (0,1). Default 0.95.
digits: Integer. Number of decimal places. Default 3.

Value

list with: - est: LR+ = Se / (1 - Sp) - std.err: EE(LR+) by delta method from the variance in log-LR+ - CI1.sl: lower limit (Simel, log-normal) - CI.su: upper limit (Simel, log-normal) - CI.gnl: lower limit (Gart & Nam) - CI.gnu: upper limit (Gart & Nam)

Details

Evaluating of Binary Diagnostic Test (EBDT)

This function calculates the Positive likelihood ratio (LR+) with Simel and Gart - Nam ICs

Requires a `gn_plr()` function in the environment and `rootall()` function in the environment (the robust version reviewed above is suitable).

References

Agresti, A., (2002). Categorical Data Analysis. John Wiley and Sons, New York.

Agresti, A., Coull, B.A., (1998). Approximate is better than ‘exact’ for interval estimation of binomial proportions. The American Statistician, 52:119 – 126.

Gart, J.J., Nam J., (1988). Aproximate interval estimation of the ratio of binomial parameters: a review and corrections for skewness. Biometrics, 44: 323 – 338.

Montero-Alonso, M.Á.(2010). Intervalos de confianza y contrastes de hipótesis para parámetros de tests diagnósticos binarios, http://hdl.handle.net/10481/4879

Simel D.L., Samsa, G.P., Matchar, D.B., (1991). Likelihood ratios with confidence: sample size estimation for diagnostic test studies. J. Clin Epidemiology, 44(8): 763-770.

Pepe, M. S. (2003). The statistical evaluation of medical tests for classification and prediction. Oxford University Press.

Zhou, X.-H., Obuchowski, N. A., y McClish, D. K. (2011). Statistical Methods in Diagnostic Medicine (2.ª ed.). John Wiley & Sons.

Examples

ebdt_plr(40, 5, 10, 45)
#> 
#>  P O S I T I V E   L I K E L I H O O D   R A T I O 
#> ---------------------------------------------------
#> 
#> Positive Likelihood Ratio estimated is: 8 
#> Standard error estimated is: 3.441 
#> Simel 95 %CI for LR+ is [ 3.443 ; 18.587 ]
#> Gart-Nam 95 %CI for LR+ is [ 3.687 ; 18.578 ]
#> 
#> Gart-Nam CI is narrower than Simel CI.
#>