Dear Statalist community,

I would like to request your help for implementation of a specific econometric model that I want to apply to my data.

I am investigating charitable donation responsiveness to changes in transitory income and available (non-working) hours. For this I exploit within-individual variation from an unbalanced short panel. I will have about 500-700 usable individual observations.
Donations are a corner solution response because they are restricted to be non-negative, leading to many observations of 0 donations.

Based on chapter 17.8 of Wooldridge (2010) I have established that the unobserved effects Tobit model would be most suited out of all panel data model options for corner solution responses.
I feel like I still need two stages (two-part model) to split the participation decision (donating a positive or 0 amount) from the actual donation amount.
Would any of you be able to tell me how to implement this type of model in Stata? Standard commands for panel data Tobit models only function for random effects.

In addition to donating, I will also be looking at volunteering responsiveness to changes transitory income and available (non-working) hours.
Because of the possible relation between this regression and the donation one, I was thinking of combining them by means of a Seemingly Unrelated Regressions model.
Does any of you have experience with and suggestions for using this model in combination with my above described model, which already seems complex enough on its own?

I look forward to hearing from you!

Best wishes,

Lieke