commonriskdiff using MR method in the case of double ones

helenjad — Sat, 10 Jun 2023 16:36:06 GMT

Hello, I've asked when there is a case of double zero event like how to adjust for the zero cell. What if we have a double one case, i.e. both p_h1 and p_h2 are equal to 1, we would also have variance equal to zero. What SAS would do to handle this situation? Below are the reference formula.

Thank you!

Re: commonriskdiff using MR method in the case of double ones

helenjad — Sat, 10 Jun 2023 17:10:57 GMT

In a follow-up, I have run below cases. The two cases give the same estimate:

data test1;
input strat trt $ responder $ count;
datalines;
1 Test Responder 4
1 Test NR 8
1 Pbo Responder 2
1 Pbo NR 11
2 Test Responder 0
2 Test NR 12
2 Pbo Responder 0
2 Pbo NR 13
;
run;

data test2;
input strat trt $ responder $ count;
datalines;
1 Test Responder 4
1 Test NR 8
1 Pbo Responder 2
1 Pbo NR 11
2 Test Responder 12
2 Test NR 0
2 Pbo Responder 13
2 Pbo NR 0
;
run;
proc freq data=test1;
weight count;
tables strat*trt * responder/commonriskdiff(column=2 cl=MR correct=NO);
run;
proc freq data=test2;
weight count;
tables strat*trt * responder/commonriskdiff(column=2 cl=MR correct=NO);
run;

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commonriskdiff using MR method in the case of double ones

Re: commonriskdiff using MR method in the case of double ones