Hi all,

I regress for the following panel fixed-effect model and leads to the result.

xtreg maroa osp, fe

maroa   Coef.    Std. Err.    t    P>t   [95% Conf. Interval]
osp   (dropped)
_cons  .5585492  .0015033  371.55   0.000  .5556027  .5614957

The result shows that osp was dropped, can anyone help me what was happened and how can I solve this problem?