Dear colleagues,

I would like to ask you questions because I have come across a task that I do not understand while operating STATA17.
I would appreciate it if someone could share their wisdom with me.

Respectfully,

Taro
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Qn 1:
Suppose two variables var1(0=No, 1=Yes) and var2(0=Neg, 1=Pos) are presented. Assuming that these two variables are in an interaction relationship, I understand that the command with ## should be used when there is a statistically significant difference between the command with ## and the command without ## in the LR Test.

Subsequently, it is my understanding that in the Cox model, lincom is used as follows

stcox i.var1##i.var2 i.var3 i.var4 i.var5
lincom 1.var1+1.var1#1.var2, hr

Is the above lincom command correct? If this is not correct, please let me know what corrections should be made.

Qn 2:
I would like to know what this lincom command reports.

Qn 3:
The following is a question about the interaction term when using stsplit to create a new variable about time.

Suppose we create two new variables, var1time0 and var1time1, by combining timeint, a time variable, with var1 of Qn1.
Using these new two variables(var1time0 and var1time1), we need to include var2 var3 var4 var5 when we create the final Cox model. Since the original var1 and var2 were in an interaction relationship, it is assumed that the new var1time0, var1time1 and var2 will be in an interaction relationship respectively. In such a case I would like to know ifI need an command to check interaction as below. If so, I would like to know if the following command be correct?

stmh var2, by(var1time0)
stmh var2, by(var1time1)

Qn 4:
If var1time0 and var1time1 are found to be in an interaction relationship with var1 respectively, the cox command would be as follows, is it correct?

stcox i.var1time0##i.var2 i.var1time1.##var2 var3 var4 var5

Qn 5:
The created the variables var1time0 and var1time1 derived from var1, a LR test with was performed to examine interaction with the original command.

If I want to do this LRTest on Qn 4 command, I would like to know what command that would be?

Please forgive my numerous questions. Thank you in advance.

Respectfully,

Taro