There is no command for a parametric conditional fixedeffects
model, as there does not exist a sufficient statistic allowing the fixed effects to be conditioned
out of the likelihood. Honore′ (1992) has developed a semiparametric estimator for fixed-effect tobit
models. Unconditional fixed-effects tobit models may be fit with the tobit command with indicator
variables for the panels; the indicators can be created with the factor-variable syntax described in
[U] 11.4.3 Factor variables. However, unconditional fixed-effects estimates are biased.