Fluorite | Level 6

## Type 3 Analysis of Effect in Logistic Regression

In Logistic Regression, the Type 3 Analysis tests are performed to test the statistical significance of each input. What exactly is the statistical test?

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SAS Super FREQ

## Re: Type 3 Analysis of Effect in Logistic Regression

If you are asking what type of test the Type3 tests are, they are Wald chi-square tests if done by PROC LOGISTIC. If they are done by PROC GENMOD, they are likelihood ratio chi-square tests by default unless the WALD option is specified in the MODEL statement. But if the REPEATED statement is used in PROC GENMOD, then they are score chi-square statistics by default (again, WALD option makes them Wald chi-squares).

6 REPLIES 6
Super User

## Re: Type 3 Analysis of Effect in Logistic Regression

I don't understand your question. Do you mean pick up the most significant variables ?

``````proc logistic data=sashelp.class;
model sex=age weight height/selection=stepwise;
run;``````
Diamond | Level 26

## Re: Type 3 Analysis of Effect in Logistic Regression

@MLAC wrote:

In Logistic Regression, the Type 3 Analysis tests are performed to test the statistical significance of each input. What exactly is the statistical test?

https://documentation.sas.com/?docsetId=statug&docsetTarget=statug_introglmest_sect015.htm&docsetVer...

In layman's terms, Type III tests are what you would use if there is no particular ordering of the predictor variables, each is considered to be entered into the model last, to see if it adds any predictive value. (I think) PROC LOGISTIC only uses Type III anyway, the other types of tests are for PROC GLM and similar procedures, and it is called Type III in PROC LOGISTIC just to keep the naming consistent with other modeling procedures. (A case where you would have a definite ordering is a polynomial model, where linear term is entered first, and quadratic term is entered second, and so on, in which case you would use Type II test; but you don't mention anything like this, so Type III is appropriate)

--
Paige Miller
Fluorite | Level 6

## Re: Type 3 Analysis of Effect in Logistic Regression

Is the type lll test Chi-Square Association test on each input?
Diamond | Level 26

## Re: Type 3 Analysis of Effect in Logistic Regression

The specific output table you want says "Type 3" (or maybe "Type III") in the header above the table.

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Paige Miller
SAS Super FREQ

## Re: Type 3 Analysis of Effect in Logistic Regression

If you are asking what type of test the Type3 tests are, they are Wald chi-square tests if done by PROC LOGISTIC. If they are done by PROC GENMOD, they are likelihood ratio chi-square tests by default unless the WALD option is specified in the MODEL statement. But if the REPEATED statement is used in PROC GENMOD, then they are score chi-square statistics by default (again, WALD option makes them Wald chi-squares).

Fluorite | Level 6

## Re: Type 3 Analysis of Effect in Logistic Regression

Thanks. I was wondering if it is Wald Chi-Square test. Thanks for the confirmation.
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