Hi,

I was reviewing the example in the Treatment Effects user guide on page 68 where it uses the following code:

use https://www.stata-press.com/data/r17/trip1
etpoisson trips cbd ptn worker weekend, treat(owncar = cbd ptn worker realinc) vce(robust)
After executing the command I am receiving the following error message:

_etpoisson_init(): 3010 attempt to dereference NULL pointer
<istmt>: - function returned error
Looking for guidance as to if there is a problem with how the command is written or a different issue with Stata. I am using Stata/BE 17.0

Thanks,
Bryan