Difference in Risk Ratio stats between JMP 15 & JMP 16?

[#1]

OK, have I got a question for y'all!  I'm teaching survival analysis and looking at Proportional Hazards Fit and Risk Ratios.  In JMP 15 I'm getting a Prob>Chisq of <.0001 for my risk ratios (yes, it's an odd dataset where the differences in survival are rather large) with understandable 95% confidence limits.  I've assumed this is testing the Ho that the risk ratio is not significantly different from a value of one.  (Could be wrong there.)  In JMP 16, however, evaluating the exact same data, I'm getting a Prob>Chisq of 0.9987 and zero for the lower 95% CI and nothing for the upper.  Can anyone explain what is going on here?

[#2]

Steve, I would report this anomaly to JMP Technical Support ([email protected]). It looks like a bug to me. Could be a code change that caused a regression. We usually have unit tests to catch such things.

I notice that the Wald chi-square is calculated correctly but it is way different from the likelihood ratio chi-square, which is also calculated correctly. I also notice that you have complete separation in the response, which can be a problem case.

What if you treat it as a nominal logistic regression?

[#3]

Mark,

Thanks for taking the time to look at this.  The data itself is artificial and used for teaching survival analysis, so it is designed to have a significant difference (although it is a rather large difference).  In the past there hasn't been a problem interpreting the numbers.  I'm not sure how one would treat this as a nominal logistic regression given the structure of the data.  I will send the question over to tech support and see what they can come up with.