Re: logistic regression: number of cases per category

Posted by waqas imran on Dec 24, 2010; 4:05am
URL: http://spssx-discussion.165.s1.nabble.com/logistic-regression-number-of-cases-per-category-tp3316148p3317358.html

Mr Jan!

The biggest problem that comes to small samples is their testing. During modelling when the parameters movetoward the testing they mostly appears to be very large over or under estmated and does not shows any significance of the model. You can face problem during justification of interpretation of model estimates.

In SPSS the minimum cases accpeted for the logistic regression are 60. It doesn't matter, whether any catagory of your Dept. variable has less then 60 but the sum of all catagories of dependent variable (whether its dichotomous or nominal or ordinal or catagorical) should not be less than 60. Nut in such situation you will face the problems which i mentioned in my first para.

Do not make more than 2 two catagories of the indicators, try to supress them so that numbers would not distribute too much.

or

Try probit, tobit models e.t.c. or another from jthe literature relevent to models for qualitative data or for dummy/dichotomous dependent variables.

Best of Luck