character string. Which coefficients should be returned?
('start' for starting values provided by the user,
'ols' for coefficients estimated by OLS,
'grid' for coefficients obtained by the grid search,
or 'mle' for coefficients estimated by Maximum Likelihood).
TRUE, additional parameters are returned:
(with u ~ N+(
sigmaSq * ( 1 -
(with v ~ N( 0,
Please note that
sigmaU are not
the variance and standard error, respectively, of u.
If the model is an error components frontier
also the following additional parameters are returned:
varU = the variance of u,
varU / (
Please note that the variance of u
usually differs between observations
if the model is an error component frontier with ‘time effect’
or an efficiency effects frontier.