st: Heckman selection estimates

[Renuka Metcalfe <rm18203@yahoo.co.uk>]

Dear Statalisters

I am using a cross-section data and the variables are
not continuous. Heckman ML estimates provides some of
the following 

             coeff    z stat
/athrho      -.098   -0.24

/insigma   -2.41    -59.62
                  Robust Standard error
rho       -0.097   0.399
sigma     0.089   0.0036
lambda    -0.0087 0.0359


When I estimated the Heckman twostep I get some of the
following:
         coeff   z stat
lambda   -0.067   0.4607
                 Robust standard error
rho     -0.647 
sigma 0.10
lambda -0.067   0.460

I would be grateful if you would let me know how one
would best interpret the significance of the above
results. If you need further information please let me
know.

Many thanks




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