Given the model
$y =\beta_0 + \beta_1 x_1 + \beta_2 x_2 + u $
where $x_1$ and $x_2$ have completely different scales and units, is it possible to test whether their impact on $y$ is the same? i.e. is there a specific test for this?
I don't think testing $H_0:\beta_1 = \beta_2$ is the right thing to do because of the different interpretations of the estimates.