st: Use ml to fit for simultaneous bivariate probit with partial observability

[健 张 <victerzj2@yahoo.com.cn>]

Hi, all:
I am trying to write my ml code to fit for a simultaneous bivariate probit with partial observability case. It is similar to Feinstein (1990)'s DCE model.
Y1i=X1i*b+ui
Y2i=X2i*c+F(X1i*b)*d+vi
Although, stata has the predefined command, biprobit (...)(...), partial for the partial observability case, the help file of biprobit does not give an answer for how to code the simultaneous case with F(X1i*b) in the second equation. Therefore, I plan to write my own ml code to deal with the problem. So far, I have had the right likelihood evaluator and I know I should use the code similar to ml model lf bipp_lf (Y1i=X1i)(Y2i=X2i......)
However, I dont know how to include F(X1i*b), which is P(Y1i=1), into the second equation. sSince it is also a partial observability case and I only know the product of Y1i*Y2i, I can not simply put Y1i in the second equation.  
Any comment is welcomed. Thank you in advance!!
 
 
Best,
Jian 

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