hi Friedrich and shehzad
Thanks for the suggestions. To make my problem clrear, here is the way my model look
Y1=sellers Y2=buyers
biprobit y1 y2 x1 x2 x3 x4 (pw=weight)
Here I want to eastimate two selection parameters for both regimes, so that I can use them in the second step which is weighted two stage least square. I want to use this selection parameters as an instrumental variables in my second model, which looks like;
ivreg y1 x1 x2 (invmills1 = x4 x5) [pweight = weight)
ivreg y2 x1 x2 (invmills2=x4 x5) [pweight = weight)
Invers mills here is the selection parameter from the biprobit, which considers the factors that affect the decision to sell and/or buy - in this case x3 x4 . This is what I thought if i am right, So I hope I made the problem clear now.
thanks for your time and suggestion again.
sami
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
