Dear Statalist members,

I have been trying to implement CRS Input-oriented Two-stage DEA Modelin my paper. We have data of 223 banks in 18 countries over 13 years and we applied DEA model using stata with 4 input vars and 3 output vars:
However when run the test with the following command I receive an error:

Code:
dea in1 in2 in3 in4 = out1 out2 out3, rts(crs) ort(in) stage(2)
Code:
variable dmu not found (error in option rownames())
Can you please advise what might be the problem.
Your help will be much appreciated as always.
Thank you in advance.
Petko Bachvarov