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Calculating an odds ratio with an empty box

How can I calculate an odds ratio with an empty box that would put a zero in the denominator? How can I get a confidence interval?

 

Re: Calculating an odds ratio with an empty box

We can help you if you give us more information.

 

• How are you using JMP?
  • Which platforms are you using?
  • Which models are you using?
• Are you working from a categorical response (data) or do you have a function for the probabilities or odds (model)?
• Are you writing a JMP script?
  • What kind of empty box are you using?
• What is the scenario in which the denominator would be zero?

Re: Calculating an odds ratio with an empty box

Thanks Mark. 

I believe I am using JMP 15.

 

I am using Fit X by Y with categorical variables.  The "positive" outcomes occurs in the intervention group 100% of the time, so I believe that when I ask for an odds ratio, it can't be calculated because the other outcome occurs 0% of the time (and so there is a 0 in the denominator).

 

I've read about using a small value in place of the 0, in which case I can just calculate an odds ratio by hand, but I'd like to get a 95% CI.  I would think that one end of the 95% CI would be infinite...?

 

Katherine

Re: Calculating an odds ratio with an empty box

I see. I am not familiar with this 'trick,' so I cannot advise you. I imagine, though, that the trick assumes large counts or else it would drastically affect the estimation of the odds ratio and its interval.