Hello everyone,

this is my first post, so please be kind and understanding if I don't meet the forum norms.

So my regression equation was: reg amount12 ib1.lng_origins c.pca_generaltrst1 ib6.religion controls
The outcome variable is amount12=amount remitted in past 12 months, lng_origins=language origins in SA such as (Sotho, Venda, Tsonga etc) and religion=Atheists, christians etc.

So the very first problem that I have is that if I only look at the amount remitted of those that remit I may have selection bias. I cannot use a heckman because my selection equation does not have a variable that is different from the second stage so the exclusion restriction is violated.

Then I talked to a professor and he said that I should simply recode the missing values in the amount remitted to zeros because those people are not remitting any amount. So I did that and I also recoded two other variables with missings to zeros that I want to include as controls because I figured that otherwise stata only takes the values into account that are non-missing but to account for selection bias it has to take all the observations into account right? These are the control that I recoded: (1) relationship to remittance receiver (2) frequency of remittances.

Now I cant use OLS because the error terms are not distributed normally and I have a loooot of zeros which is why I thought I may be able to use a zero inflated negative binomial regression. Then in inflate() I would plug in my logit regression (all variables & controls without the outcome variable) that estimated whether a person remits or not:

zinb new_amount12 ib1.pop_lngorigins c.pca_generaltrst1 ib6.religion controls, inflate(ib1.pop_lngorigins c.pca_generaltrst1 ib6.religion other controls)

Unfortunately, the inflate regression does not give me the same or similar results as the logit regression that I did already, why is that? Can I still use the coefficients that I get for amount remitted?

Please note that this is a master thesis and that it does not have to be perfect (I would like it to be but I am pretty much new to these models so I think it is very normal that it will not be perfect right away).Thank you so much for your help in advance!!