st: Questions about selmlog and svyselmlog

["Yu(Sophia) Zhang" <sophia.zhangyu@gmail.com>]

Dear statisticians,

    I am now working on my dissertation and am stuck by a STATA command.
Basically, I want to run Heckman correction based on the multinomial logit
model. I am going to use the command selmlog. However, a strange error shows
up like this:

Non-missing values of dependent variable for more than one outcome
variable _m* not found

   I guess it might be associated with this statement in the help file:

1) In the output, selmlog adds to varlist a series of variables labelled
_m[depvar_m value], except for the dhl option

2) The outcome variable depvar is observed for only one value of depvar_m.
It is important that depvar should have missing values for any other value
of depvar_m.

   But still cannot figure out what's wrong.

   In addition, when I want to control for sampling weights by running the
command svyselmlog, I get another error:

data not set up for the old survey estimation commands; use svyset under
version control or use the new svy prefix.

  But there is no "svy: selmlog" command in STATA 11.....

    I wonder if someone could kindly give me some hint for these two
problems. I have asked several people but no one were familiar with this
problem.

    I appreciate your help very much.

    Sincerely,

    Yu

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