> More specifically, this is where you need data which does not and cannot exist. This is wrong. All important work in my field in the past 25 years has been

> More specifically, this is where you need data which does not and cannot exist. This is wrong. All important work in my field in the past 25 years has been empirical. > Any model which assigns numeric "estimates" for these costs and benefits so they can be compared is substituting the authors' own subjective valuations in place of those of those who will be affected by the policy. Very, very wrong. You’ll never get away with picking your own parameter values in modern empirical IO. If you don’t know the field that’s fine. I probably don’t know your field either. But don’t make these overconfident and totally wrong claims about what’s done in a field you don’t know anything about.