Table 8.

Robustness analysis of alternative regression methods.

Dependent	${\theta }^{\prime }$	${\theta }^{\prime }$	${\theta }^{\prime }$	${\theta }^{\prime }$
Method	FE	FE	FE	FE
$x_1$	0.275*** (23.77)	0.181*** (13.71)
$x_2$			0.831*** (35.22)	0.695*** (20.26)
Control variables	No	Yes	No	Yes
${\tau }_i$	Yes	Yes	Yes	Yes
N	486	486	486	486
$R^2$	0.852	0.888	0.913	0.919

Notes: The parentheses in the table are t-statistics or z-statistics, and ***, **, and * indicate passing significance tests at the 1%, 5%, and 10% levels, respectively.