variable RR already defined variable Lower not found error during Mantel–Haenszel estimate of the rate ratio

[Khaled Kotb]

Hello everyone,
I hope you're all doing fine.
Firstly, I wanted to express how grateful am I for your kind help, it really helped me very much as a beginner. Thanks a lot, I really appreciate it.

Secondly,

I've used the following command

stptime, by(rs2228001) per(100)
stmh rs11615, compare (0,2 )

I keep getting this error:
variable RR already defined
variable Lower not found


when I'm trying to get Mantel–Haenszel estimate of the rate ratio between 0 and 2 values of rs11615 using the command

where rs11615 is a categorical variable with three values 0,1,2

Before that, I've done many survival time analyses as Kaplan Meier, and they all went pretty fine, but this one keeps getting this error.

How can I avoid that error ?

[Andrew Musau]

Do you have a variable named "RR" in your dataset? I can only replicate this error if that is the case. Maybe you can rename that variable in case it exists.

cap rename RR VarRR
stptime, by(rs2228001) per(100)
stmh rs11615, compare (0,2 )

[Khaled Kotb]

No I don't have a variable called RR in my dataset.

Maybe the variable originated from the survival time analysis that I used, but, I haven't generated such variable intentionally.

Any insights what might be the error ?

[Andrew Musau]

Did including

cap rename RR VarRR

before running stmh not resolve the problem? I think you should raise the issue with Stata Technical Services - "RR" is not a reserved variable name. Here is a reproducible example that you can send to them.

webuse diet, clear
stset dox, origin(time dob) enter(time doe) id(id) scale(365.25) fail(fail==1 3 13) noshow
gen RR= .
stmh month, compare(11, 12)

Res.:

. stmh month, compare(11, 12)

Mantel-Haenszel estimate of the rate ratio
  comparing month==11 vs. month==12

variable RR already defined
variable Lower not found
r(111);