st: Re: joint effect of two endogenous variables

[xueliansharon <xuelianstata@gmail.com>]

>The first thing that comes to mind is that you will need to make 
>sure that the unit of y1 and y2 are equal, if y1 is in seconds and 
>y2 is in liters, than what does a unit change mean? A common 
>approach is to standardize variables, i.e. subtract the mean and 
>divide by the standard deviation. 

Maarten, my y1 is people's age started to work, y2 is years of schooling,
what I want to get is the joint effect when people started to enter the
labor market one year later and receive one more year of schooling. 

But I didn't understand why "constraining the effects to be equal" could
compute the joint effect, could you explain it more explicitly?

Thank you in advance.
Sharon
-- 
View this message in context: http://statalist.1588530.n2.nabble.com/joint-effect-of-two-endogenous-variables-tp5456810p5457339.html
Sent from the Statalist mailing list archive at Nabble.com.
*
*   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/