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I want to do a logistic regression in SPSS. However, since I analyse unemployment spells the subjects are sometimes repeated (violating the independence assumption of the regression). One way of removing the within subject variation is by applying a Genlin model with the repeated subject subcommand (in essence a GEE model). Thus, I tried out a Genlin model with binomal probability and the logit link, comparing it to a standard logistic regression. I used the exact same variables in the two procedures.

However, the results that was delivered from the Genlin procedure was inverted relative to that of the logistic regression. For instance: Exp(B) for women (of the independent variable sex/gender) was just above 2.0 in logistic regression while being at 0.49 in Genlin. The same happened with every independent variable.

  • Any suggestions to why the results of the Genlin procedure is inverted?
  • Is there any way to get the Genlin results in accordance to the logistic regression?
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    $\begingroup$ Check the other tables of the outputs and look for the coding schemes. These two modules might have coded your sex variable differently; one might have used male as reference while the other one used female. $\endgroup$
    – Penguin_Knight
    Commented Oct 15, 2013 at 1:10
  • $\begingroup$ No, that is not it. I have been very careful to get the same reference for every variable in both logistic and Genlin. In every respect (since I have left out the repeated subcommand) the models should be the same. $\endgroup$
    – Cookie Monster
    Commented Oct 15, 2013 at 6:10
  • $\begingroup$ It's the reference of the outcome that matters. How is this coded? $\endgroup$
    – Jeremy Miles
    Commented Feb 19, 2014 at 17:00

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This is because the default for the reference category in GENLIN is FIRST. Try changing this to LAST.

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