Hi,
I am trying to use Heckman two-step model in order to take care of sample selection bias. I have a question regarding the second stage. here is my model:

heckman SC rmshi mc1 lptd lpbc iros fss dltts B2B res ci yd* id*, select(lpd= rmshi fss mc1 lptd iros fss dltts res ci yd* id*) twostep mills(mymills)

lpd is a bianry variable (1= main group, 0=the matched group)

my question is after running this model, should I take mymills (the inverse mills ratio) and use it to estimate below model or not:

reg SC rmshi mc1 lptd iros fss dltts B2B res ci yd* id* mymills if lpd==1