# Excluding observations from the sample (data-file)

**Hi all**,
I’m running a regression analysis. Unfortunately, I recognized that some of the observations are associated with errors, and I want to exclude these observations from the regression. The criterion I want to use in an exclusion of observations is that the sum of three of the variables in the sample is zero, i.e.: I want to exclude observations from the regression which fulfills the criterion; x1 + x2 + x3 = 0. I do **NOT** want to exclude variables, only observations which fulfill the criterion. Question: Is it possible to use a Shazam-code to solve the problem. I looked into the SKIPIF-command but couldn’t find a way out of it.

Best regards!

Thank for your help :)