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LHK
Calcite | Level 5 LHK
Calcite | Level 5

Hello Experts:

I run into a difficulty to explain which independent variable is more predictive when running a Proc Logistic.

In my proc Logistic procedure, I modeled the dependent variable (Event = '1'), see code below:

proc logistic data=data_test;

model p_flag (event = '1') = var1 var2 var3 / selection=stepwise;

run;

Then I get this results for the stepwise selection:

Summary of Stepwise Selection
StepEffectDFNumber InScore Chi-SquareWald Chi-SquarePr > ChiSqVariable Label
EnteredRemoved
1var3 112006.955 <.0001 
2var2 12150.3232 <.0001 
3var1 1343.6837 <.0001 

and the likelihood:

Analysis of Maximum Likelihood Estimates
ParameterDFEstimateStandard ErrorWald Chi-SquarePr > ChiSq
Intercept1-4.14280.11421316.869<.0001
var111.0830.155648.4503<.0001
var21-0.12560.00706316.7223<.0001
var310.27540.004633541.0916<.0001

And the odd ratios:

Odds Ratio Estimates
EffectPoint Estimate95% Wald  Confidence Limits
var12.9542.1774.007
var20.8820.870.894
var31.3171.3051.329

 

So my question is:

Which one of the 3 variables is the most predictable for p_flag =1? In the likelihood test, which output field I need to look into: estimate vs. Wald Chi-square?

 

Thanks a lot!

LHK

3 REPLIES 3
PaigeMiller
Diamond | Level 26

I don't think there is an answer to your question. I don't really even understand what you want when you say "most predictable". It doesn't make sense to me to just use one predictor given these results.

--
Paige Miller
Ksharp
Super User

I will pick up Wald Chi-Square, since it is statistic .

And var3 has the biggest Chi-Square ,so its Pr > ChiSq should be smallest. therefore, var3 is most significant variable.

PaigeMiller
Diamond | Level 26

@Ksharp wrote:

I will pick up Wald Chi-Square, since it is statistic .

And var3 has the biggest Chi-Square ,so its Pr > ChiSq should be smallest. therefore, var3 is most significant variable.


True, but the question was not "most significant variable", it was "most predictable", which seems to me is a meaningless question, and different than "most significant".

 

Anyway, the idea of selecting one of these three variables is the "best" seems like a very poor idea.

--
Paige Miller

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