st: missing standard errors when using nl command

["stephen hynes" <stephenhynes@hotmail.com>]

Hi all,

I am using the nl command to fit a nonlinear function to my dependand variable by least squares. I have a dataset with 6 years of observations on approx. 5000 individuals. I am carrying out a variance covariance analysis using the minimum distance method and am trying to fit an appropriate econometric specification to my error component model (for Irish earnings). When I run my model specification using nl I get no results back for my standard errors, only dots. Can anyone tell me why this may be so. Are the number of years of observations too small?

Stephen

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