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Logistic regression parameter estimates opposite of expected

Oct 25, 2010 11:14 AM
(1995 views)

Hello All,

I am a JMP newbie and to learn about JMP, I've been re-analyzing some of my old data using JMP. When I run a logisitic regression model with an ordinal dependent variable (0 or 1) and a continuous variable as the independent variable (a number between -0.5 and 0) the parameter estimates I get are numerically opposite to what I would expect. The parameter estimate for the independent variable (X) is -1.513 but when I run the same analysis using SAS, EpiInfo, Mac StatPlus, or R, I get 1.513. The p-value is the same and the intercept parameter estimate is also opposite. What am I missing to get JMP to work properly? I'm still using the free trial period to figure out whether I want to buy JMP or not... Thanks.

Nick

I am a JMP newbie and to learn about JMP, I've been re-analyzing some of my old data using JMP. When I run a logisitic regression model with an ordinal dependent variable (0 or 1) and a continuous variable as the independent variable (a number between -0.5 and 0) the parameter estimates I get are numerically opposite to what I would expect. The parameter estimate for the independent variable (X) is -1.513 but when I run the same analysis using SAS, EpiInfo, Mac StatPlus, or R, I get 1.513. The p-value is the same and the intercept parameter estimate is also opposite. What am I missing to get JMP to work properly? I'm still using the free trial period to figure out whether I want to buy JMP or not... Thanks.

Nick

4 REPLIES 4

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Re: Logistic regression parameter estimates opposite of expected

Any chance you reversed the 0's and 1's when creating the JMP file?

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Re: Logistic regression parameter estimates opposite of expected

Hi,

I am also having the same issue...

In my dataset, the outcome variable, "madeit", is nominal, Yes/No and "FullDayCount" is continuous. When running Fit model - Logistic regression JMP seems to express Log odds of No versus Yes, instead of Yes versus No. Is there a way to reverse it? The stata result is correct and opposite of what JMP shows - please see attached images.

Thank you for helping me figure this out.

Patrick

JMP 10 windows version:

Stata 11 Mac:

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Re: Logistic regression parameter estimates opposite of expected

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Re: Logistic regression parameter estimates opposite of expected

Thank you very much! Your suggestion fixed my issue.