topic Re: Finding a cutoff value in multivariate logistic regression? in Statistical Procedures

Finding a cutoff value in multivariate logistic regression?

Dcicantab5 — Fri, 08 Jul 2016 12:54:15 GMT

Hi,

Need advice: I am trying to find cutoffs in a multivariate logistic regression model composed of a categorical predictor and several continuous variables:

PROC LOGISTIC DATA=work.sdcrossvalid OUTEST=_SNSP_EST;

CLASS Bleed;

MODEL Outcome(event='1')=

Age_yr_

Plt

Sr_Creat

AST

ALT

HCO3

Lactate

Bleed/ EXPB ;

To determine the cutoff value, I use the following formula:

X_value = (Logit - intercept)/(Sum of estimates of all predictor variables), as adapted from:

ref: Paper 231-2008

A Macro For Getting More Out Of Your ROC Curve:

X_VALUE = (LOG(_PROB_/(1-_PROB_))-INTERCEPT)/&XVAR

This paper only refer to a single continuous variable. What if you have several?

Is my denominator (Sum of estimates of all predictor variables) correct?

Re: Finding a cutoff value in multivariate logistic regression?

Ksharp — Sat, 09 Jul 2016 06:18:00 GMT


If you have multiple levels for Y , that would lead you to two kind of logistic model:
1) cumulative logistic
2)generalize logistic


The cutoff value means nothing for these two kind of model.
If it is binary logistic model, CTABLE could give you a good vision to cutoff value.


proc logistic data=sashelp.class;
model sex=age weight height/ctable;
run;

Re: Finding a cutoff value in multivariate logistic regression?

TomHsiung — Sat, 03 Aug 2024 09:16:17 GMT

Thanks for sharing the code lines and this is what I intend to learn today.

Re: Finding a cutoff value in multivariate logistic regression?

Ksharp — Sun, 04 Aug 2024 00:36:00 GMT

Here is a special macro for that purpose .
https://support.sas.com/kb/25/018.html