topic Re: Sensitivity specificity LR in Statistical Procedures

Sensitivity specificity LR

antor82 — Sat, 20 Jul 2019 08:11:01 GMT

Hi all

is there a macro/code that mimics in SAS what pROC and bootLR do in R?

my aim is to calculate bootstrap threshold, sensitivity, specificity, LT+ and LR- along with 95% CI

Tks!

Re: Sensitivity specificity LR

PaigeMiller — Sat, 20 Jul 2019 11:11:52 GMT

@antor82 wrote:

is there a macro/code that mimics in SAS what pROC and bootLR do in R?

What do pROC and bootLR do?

Re: Sensitivity specificity LR

antor82 — Sat, 20 Jul 2019 11:16:37 GMT

bootLR Computes the (positive/negative) likelihood ratio with appropriate, bootstrapped confidence intervals

pROC computes threshold sensitivity and specificity for a given value with appropriate, bootstrapped confidence intervals

Re: Sensitivity specificity LR

PaigeMiller — Sat, 20 Jul 2019 11:21:08 GMT

Normally, a likelihood ratio is computed to test to see if a statistic is significantly different than some quantity ... what statistic is being tested, and in what context?

Normally, bootstrap confidence intervals are computed to see some measure of variability of a particular statistic ... what statistic is being tested, and in what context?

Re: Sensitivity specificity LR

antor82 — Sat, 20 Jul 2019 11:33:37 GMT

I’m testing if a new parameter is predictive of an outcome.
My sample size is small (60 patients).
Other authors did the same and provided AUC, cut-off (with corresponding sensibility, specificity, LR+ and -) calculated after bootstrapping

Re: Sensitivity specificity LR

PaigeMiller — Sat, 20 Jul 2019 11:38:57 GMT

I’m testing if a new parameter is predictive of an outcome.

Some sort of regression??? A decision tree??? A Neural Network??? What is the exact type of model?

Other authors did the same and provided AUC, cut-off (with corresponding sensibility, specificity, LR+ and -) calculated after bootstrapping

Logistic regression?? Decision tree?? Neural Network?? Other???

Re: Sensitivity specificity LR

antor82 — Sat, 20 Jul 2019 11:48:37 GMT

Logistic regression

Re: Sensitivity specificity LR

PaigeMiller — Sat, 20 Jul 2019 13:09:07 GMT

@Rick_SAS has written the definitive guide to bootstrapping in SAS

https://blogs.sas.com/content/iml/2018/12/12/essential-guide-bootstrapping-sas.html

Re: Sensitivity specificity LR

antor82 — Sat, 20 Jul 2019 16:39:13 GMT

Tks!