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Re: st: Using a Tobit regression with the Heckman correction
From
"J. Boreham" <[email protected]>
To
[email protected]
Subject
Re: st: Using a Tobit regression with the Heckman correction
Date
20 Dec 2011 20:27:27 +0000
Thank you Nick and Tirthankar, that seems to be working perfectly now!
On Dec 20 2011, Tirthankar Chakravarty wrote:
As Nick pointed out, your code seems to be incomplete.
Other than that you have got the syntax of -craggit- wrong. I am
assuming that "fee" is your positive continuous variable? If so, "fee"
and its determinants go into the "second()" option and the binary
indicator (your "transferred" variable and its determinants) go first.
This is in contrast to t the syntax of -heckman-.
T
On Tue, Dec 20, 2011 at 11:26 AM, Nick Cox <[email protected]> wrote:
Your syntax appears truncated as the option -second()- lacks a closing
right parenthesis.
-craggit-, or more likely -ml-, is having difficulty fitting your
model. Try a simpler model or helping out the program by suggesting
better initial values.
Nick
On Tue, Dec 20, 2011 at 7:19 PM, J. Boreham <[email protected]> wrote:
Thanks again for your help, that does appear to be what I'm after.
However, when I use it, I get the error message:
"could not calculate numerical derivatives
discontinuous region with missing values encountered"
The code I used was:
******** craggit fee age agesq curr_app curr_goal_d curr_goal_m
curr_goal_f, second(transferred age agesq curr_app curr_goal_d
curr_goal_m curr_goal_f ********
Do you have any idea what may have caused this error?
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