topic Re: Sensitivity and Specificity Output for an ROC Curve in Statistical Procedures

Sensitivity and Specificity Output for an ROC Curve

gabybarber — Tue, 19 Jan 2021 14:49:10 GMT

I am using data from PRAMS (which uses a complex survey design) to create an ROC curve using predicted probabilities. How can I see the sensitivity and specificity for my various cutoffs, keeping in mind the complex sample?

Thanks!

Re: Sensitivity and Specificity Output for an ROC Curve

Rick_SAS — Wed, 20 Jan 2021 12:34:58 GMT

The ROC curve IS the set of sensitivities and specificities. I assume when you say, "how can I see them," you mean you want to display the actual numerical values along the curve? If so, you can do this by using ODS OUTPUT.

Find the name of the ROC graph for which you want the values
Use ODS OUTPUT to write the graph to a SAS data set
Use PROC PRINT to display the results

For example, if you were using PROC LOGISTIC, it might look like this:

ods trace on;
proc logistic data=Data1 plots(only)=roc;
   model disease/n=age;
   ods output ROCCurve=OutROC;
run;

data OutROC2;
set OutROC;
Specificity = 1 - _1MSPEC_;
run;

proc print data=OutROC2 label;
var _SENSIT_ _1MSPEC_ Specificity;
run;

Re: Sensitivity and Specificity Output for an ROC Curve

gabybarber — Wed, 20 Jan 2021 17:19:13 GMT

Thanks! That was exactly what I was looking for - to display the numerical
values.

Re: Sensitivity and Specificity Output for an ROC Curve

gabybarber — Wed, 20 Jan 2021 18:30:32 GMT

One follow up question - I am trying to get the sensitivity and specificity for each of my exposure groups independent of the covariates I have included in the model. For example, my exposure variable is smoking (4 levels), and I have included the covariate sex in my model (2 levels). Right now, I get sensitivities and specificities for each combination of the smoking groups and sex (8 different sensitivities). I would just like to see sensitivity and specificity for each level of the exposure group (smoking), independent of sex.

Re: Sensitivity and Specificity Output for an ROC Curve

Rick_SAS — Wed, 20 Jan 2021 18:39:05 GMT

Then remove SEX from your model.