Programming the statistical procedures from SAS

LOGISTIC Turn off option

Occasional Contributor
Posts: 18

LOGISTIC Turn off option

I'm getting the following result when I do a proc logistic:

NOTE: The following parameters have been set to 0, since the variables are a linear combination of other variables as shown.

radicalYes = 1 * Intercept - 1 * abdominalYes - 1 * laproscopicYes - 1 * vaginalYes

Is there a way that I can force it not to create this linear combination?
Valued Guide
Posts: 2,108

Re: LOGISTIC Turn off option

What the LOGISTIC procedure is saying is that you have an over-parametrized model. To fix that you either need more data (so all the combinations are represented) or fewer variables.

If Radical is defined at any one of Abdominal, Laproscopic, or Vaginal, then just drop Radical, as you can estimate it's effect via the other parameters.

Doc Muhlbaier
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