Hi,
Thank you very much for your command but when I am running the triplediff, it produces the error indicating that Error in compute_did_rc(data, condition_subgroup = 3, pscores = pscores, :
The regression design matrix for control pre-treatment is singular. Consider removing some covariates. Could you please tell what does this error mean and the possible reason for the error?
Thank you very much for your help.
Best
Steven
Hi,
Thank you very much for your command but when I am running the triplediff, it produces the error indicating that Error in compute_did_rc(data, condition_subgroup = 3, pscores = pscores, :
The regression design matrix for control pre-treatment is singular. Consider removing some covariates. Could you please tell what does this error mean and the possible reason for the error?
Thank you very much for your help.
Best
Steven