This doesn't work for a large dataset, you receive an out of memory error. ... View more

You need using SAS (Unicode Support) to run your code.  ... View more

Million thanks for your help. This is what I am hunting for. Thank you very much.  ... View more

OK. Thank you for your reminder. VERY MUCH appreicated. That is what I want . Thank you very much. Jack. ... View more

Hi @Jack2012, @Jack2012 wrote: ERROR: Invalid reference value for _group. You specified ,_stratavar= GROUP ... ,_ref= 0 in the macro call, but neither variable GROUP nor variable _GROUP (which must have been used when the error message occurred) have a (formatted) value of "0". I think you really should use variable _GROUP. Then parameter _ref must get one of the values of _GROUP, i.e., 1, 2 or 3 (your choice): ,_stratavar= _GROUP ... ,_ref= 1   There also seem to be other issues. One is easy to correct: You define a macro variable OUTPUTPATH (in a %LET statement), but the macro uses _OUTPUTPATH.   ... View more

Great thanks Dave.  I see now.   Actually, we know when planning an IA, then PROC SEQDESIGN could be used to calculate the timepoints to the IA and the corresponding time to do the IA with a prespecified significance level, and targeted power with SAMPLESIZE statement.    Intuitively, I thought, how to calcute the power with prespecified timepoints, number of events/information with this.    Last but not least, I know this case now. Thank you.    Best regards,  ... View more

Rick, thank you. Yes, your understanding is absolutely correct. OK, then I will not try anymore. Thank you, and Ksharp. ... View more

I am facing the same question as well, have anybody has solution?  ... View more

I have noticed this post and read it. However, Not the answer that I am seek for. Thanks.  ... View more

Table 4 on p. 7. In the paper by Catello and Watts are for non-inferiority test for lognormal data or ratio of two geometric means. We would like to know if SAS proc power can computer the power/sample size for non-interiority test of two correlated proportions. A good example for this issue is illustrated in FDA guidance "Comparative Analysis and Related Comparative Use Human Factors Studies for a Drug-Device Combination Product Submitted in an ANDA" http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM536959.pdf In the proposed study, each subject will test for two different medical devices (old device and new device). The error rates for using old device and using new device will then be calculated. The assumption is that if a patient is good at using the old device, he/she will be also good at using the new device. In other words, the error rate for using the old device is correlated with the error rate using the new device. If we are trying to design a non-inferiority study as outlined in FDA's guidance, will SAS proc power be used for calculating the power/sample size? The FDA guidance provided examples for sample sizes that were generated using the simulation. ... View more